#include<cstdio>
#include<cstring>
#include<algorithm>
#include<set>
#define ll long long
using namespace std;
int rdn()
{int ret=0;bool fx=1;char ch=getchar();while(ch>'9'||ch<'0'){if(ch=='-')fx=0;ch=getchar();}while(ch>='0'&&ch<='9')ret=ret*10+ch-'0',ch=getchar();return fx?ret:-ret;
}
int Mx(int a,int b){return a>b?a:b;}
int Mn(int a,int b){return a<b?a:b;}
const int N=2e5+5,K=18,bs=10007,md=1e9+9;
int n,dep[N],hs[N][K+5],pre[N][K],lj[N];
int sa[N],rk[N],ht[N][K+5],bin[K+5],lg[N];
int hd[N],xnt,to[N],nxt[N],rt[N],ans;
struct Node{int x;Node(int x=0):x(x) {}bool operator< (const Node &b)const{return rk[x]<rk[b.x];}
};
set<Node> st[N];
set<Node>::iterator it,it2;
int get_lcp(int u,int v)
{int ret=0;for(int t=lg[Mn(dep[u],dep[v])];t>=0;t--)//Mn not Mxif(pre[u][t]&&pre[v][t]&&hs[u][t]==hs[v][t])//if pre[][]u=pre[u][t], v=pre[v][t], ret+=bin[t];return ret;
}
bool cmp(int u,int v)
{for(int t=lg[Mn(dep[u],dep[v])];t>=0;t--)//Mnif(pre[u][t]&&pre[v][t]&&hs[u][t]==hs[v][t])//pre[][]u=pre[u][t], v=pre[v][t];return hs[u][0]<hs[v][0];
}
void get_ht()
{for(int i=2;i<=n;i++)ht[i][0]=get_lcp(sa[i-1],sa[i]);for(int t=1;t<=lg[n];t++)for(int i=1;i+bin[t]-1<=n;i++)ht[i][t]=Mn(ht[i][t-1],ht[i+bin[t-1]][t-1]);
}
int qry_ht(int u,int v)
{if(u==v)return dep[u];u=rk[u]; v=rk[v]; if(u>v)swap(u,v);u++; int d=lg[v-u+1];return Mn(ht[u][d],ht[v-bin[d]+1][d]);
}
int mrg(int &u,int v)
{int ret=0;if(st[u].size()<st[v].size())swap(u,v);for(it=st[v].begin();it!=st[v].end();it++){st[u].insert(*it);it2=st[u].find(*it);if(it2!=st[u].begin()){it2--; ret=Mx(ret,qry_ht((*it2).x,(*it).x));it2++;}it2++; if(it2==st[u].end())continue;ret=Mx(ret,qry_ht((*it2).x,(*it).x));}return ret;
}
void dfs(int cr)
{rt[cr]=cr; st[rt[cr]].insert(Node(cr));int ret=0;for(int i=hd[cr],v;i;i=nxt[i]){dfs(v=to[i]);ret=Mx(ret,mrg(rt[cr],rt[v]));}if(st[rt[cr]].size()>1)//if!!!
    {ans=Mx(ans,dep[cr]+ret);}
}
int main()
{freopen("recollection.in","r",stdin);freopen("recollection.out","w",stdout);n=rdn();bin[0]=1;for(int i=1;i<=K;i++)bin[i]=bin[i-1]<<1;for(int i=2;i<=n;i++)lg[i]=lg[i>>1]+1;lj[0]=1;for(int i=1;i<=n;i++)lj[i]=(ll)lj[i-1]*bs%md;int he=0, tl=0;for(int i=2;i<=n;i++){pre[i][0]=rdn();hs[i][0]=rdn()+1;//+1 for cmp emptyto[++xnt]=i; nxt[xnt]=hd[pre[i][0]]; hd[pre[i][0]]=xnt;}for(int i=2;i<=n;i++){dep[i]=dep[pre[i][0]]+1;for(int t=1,d=pre[i][0];(d=pre[i][t-1]);t++){pre[i][t]=pre[d][t-1];hs[i][t]=((ll)hs[i][t-1]*lj[bin[t-1]]+hs[d][t-1])%md;}}for(int i=1;i<=n;i++)sa[i]=i; sort(sa+1,sa+n+1,cmp);for(int i=1;i<=n;i++)rk[sa[i]]=i;get_ht(); dfs(1);printf("%d\n",ans);return 0;
}

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#define ls Ls[cr]
#define rs Rs[cr]
#define pb push_back
using namespace std;
int rdn()
{int ret=0;bool fx=1;char ch=getchar();while(ch>'9'||ch<'0'){if(ch=='-')fx=0;ch=getchar();}while(ch>='0'&&ch<='9')ret=ret*10+ch-'0',ch=getchar();return fx?ret:-ret;
}
int Mx(int a,int b){return a>b?a:b;}
int Mn(int a,int b){return a<b?a:b;}
const int N=2e5+5,K=20,M=N*K;
int n,dep[N],pre[N][K],hd[N],xnt,to[N],nxt[N];
int ht[K][N],rk[K][N],sa[N],tp[N],tx[N],lm,ans;
int bin[K],lg[N],rt[N],Ls[M],Rs[M],fr[M],sc[M],sm[M],tot;
int h2[N],xt2,t2[N],nt2[N];
void add(int x,int y){to[++xnt]=y;nxt[xnt]=hd[x];hd[x]=xnt;}
void ad2(int x,int y){t2[++xt2]=y;nt2[xt2]=h2[x];h2[x]=xt2;}
void Rsort(int n,int nm,int t)
{for(int i=0;i<=nm;i++)tx[i]=0;// 0 !!!! for emptyfor(int i=1;i<=n;i++)tx[rk[t][i]]++;for(int i=1;i<=nm;i++)tx[i]+=tx[i-1];for(int i=n;i;i--)sa[tx[rk[t][tp[i]]]--]=tp[i];
}
void get_sa(int n,int nm)
{for(int i=1;i<=n;i++)tp[i]=i;Rsort(n,nm,0);for(int t=1;;t++){xt2=0; memset(h2,0,sizeof h2);for(int i=1;i<=n;i++)if(pre[i][t-1])ad2(pre[i][t-1],i);int tot=0;for(int i=1;i<=n;i++)if(!pre[i][t-1])tp[++tot]=i;for(int i=1;i<=n;i++)for(int j=h2[sa[i]];j;j=nt2[j])tp[++tot]=t2[j];Rsort(n,nm,t-1); rk[t][sa[1]]=nm=1;for(int i=2;i<=n;i++){int cr=sa[i], u=pre[cr][t-1], v=pre[sa[i-1]][t-1];rk[t][cr]=(rk[t-1][cr]==rk[t-1][sa[i-1]]&&rk[t-1][u]==rk[t-1][v])?nm:++nm;}lm=t; if(nm==n)break;}
}
int get_lcp(int u,int v)
{int ret=0;for(int t=lm;t>=0;t--)//t=lm!!if(pre[u][t]&&pre[v][t]&&rk[t][u]==rk[t][v])//preu=pre[u][t], v=pre[v][t], ret+=bin[t];return ret;
}
void get_ht()
{for(int i=2;i<=n;i++)ht[0][i]=get_lcp(sa[i-1],sa[i]);for(int t=1;t<=lg[n];t++)for(int i=1;i<=n;i++)ht[t][i]=Mn(ht[t-1][i],ht[t-1][i+bin[t-1]]);
}
int qry_ht(int l,int r)
{if(l==r)return dep[sa[l]];if(l>r)swap(l,r); l++; int d=lg[r-l+1];int ret=Mn(ht[d][l],ht[d][r-bin[d]+1]);return ret;
}
void build(int l,int r,int &cr,int p)
{cr=++tot; fr[cr]=sc[cr]=p;if(l==r)return; int mid=l+r>>1;if(p<=mid)build(l,mid,ls,p);else build(mid+1,r,rs,p);
}
void mrg(int l,int r,int &cr,int pr)
{if(!cr){cr=pr;return;} if(!pr)return;int mid=l+r>>1;mrg(l,mid,ls,Ls[pr]); mrg(mid+1,r,rs,Rs[pr]);fr[cr]=(ls?fr[ls]:fr[rs]); sc[cr]=(rs?sc[rs]:sc[ls]);sm[cr]=Mx(sm[ls],sm[rs]);if(fr[ls]&&fr[rs])sm[cr]=Mx(sm[cr],qry_ht(sc[ls],fr[rs]));
}
void dfs(int cr)
{build(1,n,rt[cr],rk[lm][cr]);for(int i=hd[cr],v;i;i=nxt[i]){dfs(v=to[i]);mrg(1,n,rt[cr],rt[v]);}if(hd[cr]){ans=Mx(ans,dep[cr]+sm[rt[cr]]);}
}
int main()
{freopen("recollection.in","r",stdin);freopen("recollection.out","w",stdout);n=rdn();for(int i=2;i<=n;i++)lg[i]=lg[i>>1]+1;bin[0]=1;for(int i=1;bin[i-1]<=n;i++)bin[i]=bin[i-1]<<1;for(int i=2;i<=n;i++){int fa=rdn(); rk[0][i]=rdn()+1;//+1!!!!! for cmp with emptydep[i]=dep[fa]+1; pre[i][0]=fa; add(fa,i);for(int t=1,d=fa;(d=pre[i][t-1]);t++)pre[i][t]=pre[d][t-1];}get_sa(n,301); get_ht();dfs(1);printf("%d\n",ans);return 0;
}