#include<iostream>
#include<algorithm>
#include<cstdio>
#define LSON rt<<1
#define RSON rt<<1|1
#define DATA(x) b[x].data
#define POS(x) b[x].pos
#define SIGN(x) b[x].c
#define LSIDE(x) b[x].l
#define RSIDE(x) b[x].r
#define WIDTH(x) (RSIDE(x)-LSIDE(x)+1)
#define MAXN 200010
using namespace std;
int n,m,c=1,d=1;
int val[MAXN],head[MAXN],deep[MAXN],son[MAXN],size[MAXN],fa[MAXN],id[MAXN],pos[MAXN],top[MAXN];
long long sum[MAXN];
bool used[MAXN];
struct Tree{int next,to;
}a[MAXN<<1];
struct Segment_Tree{long long data,pos,c;int l,r;
}b[MAXN<<2];
inline int read(){int date=0,w=1;char c=0;while(c<'0'||c>'9'){if(c=='-')w=-1;c=getchar();}while(c>='0'&&c<='9'){date=date*10+c-'0';c=getchar();}return date*w;
}
inline void add(int x,int y){a[c].to=y;a[c].next=head[x];head[x]=c++;a[c].to=x;a[c].next=head[y];head[y]=c++;
}
void dfs1(int rt){son[rt]=0;size[rt]=1;for(int i=head[rt];i;i=a[i].next){int will=a[i].to;if(!deep[will]){deep[will]=deep[rt]+1;sum[will]=sum[rt]+val[will];fa[will]=rt;dfs1(will);size[rt]+=size[will];if(size[son[rt]]<size[will])son[rt]=will;}}
}
void dfs2(int rt,int f){id[rt]=d++;pos[id[rt]]=rt;top[rt]=f;if(son[rt])dfs2(son[rt],f);for(int i=head[rt];i;i=a[i].next){int will=a[i].to;if(will!=fa[rt]&&will!=son[rt])dfs2(will,will);}
}
inline void pushup(int rt){DATA(rt)=max(DATA(LSON),DATA(RSON));if(DATA(LSON)>DATA(RSON))POS(rt)=POS(LSON);else POS(rt)=POS(RSON);
}
inline void pushdown(int rt){if(!SIGN(rt)||LSIDE(rt)==RSIDE(rt))return;SIGN(LSON)+=SIGN(rt);DATA(LSON)+=SIGN(rt);SIGN(RSON)+=SIGN(rt);DATA(RSON)+=SIGN(rt);SIGN(rt)=0;
}
void buildtree(int l,int r,int rt){LSIDE(rt)=l;RSIDE(rt)=r;SIGN(rt)=0;if(l==r){DATA(rt)=sum[pos[l]];POS(rt)=l;return;}int mid=l+r>>1;buildtree(l,mid,LSON);buildtree(mid+1,r,RSON);pushup(rt);
}
void update(int l,int r,long long c,int rt){if(l<=LSIDE(rt)&&RSIDE(rt)<=r){SIGN(rt)+=c;DATA(rt)+=c;return;}pushdown(rt);int mid=LSIDE(rt)+RSIDE(rt)>>1;if(l<=mid)update(l,r,c,LSON);if(mid<r)update(l,r,c,RSON);pushup(rt);
}
long long query(int l,int r,int rt){long long ans=0;if(l<=LSIDE(rt)&&RSIDE(rt)<=r)return DATA(rt);pushdown(rt);int mid=LSIDE(rt)+RSIDE(rt)>>1;if(l<=mid)ans=max(ans,query(l,r,LSON));if(mid<r)ans=max(ans,query(l,r,RSON));return ans;
}
void work(){long long ans=0;for(int i=1;i<=m;i++){ans+=query(1,n,1);int x=pos[POS(1)];while(x&&used[x]){update(id[x],id[x]+size[x]-1,-val[x],1);used[x]=false;x=fa[x];}}printf("%lld\n",ans);
}
void init(){int x,y;n=read();m=read();for(int i=1;i<=n;i++){val[i]=read();used[i]=true;}for(int i=1;i<n;i++){x=read();y=read();add(x,y);}deep[1]=1;sum[1]=val[1];dfs1(1);dfs2(1,1);buildtree(1,n,1);
}
int main(){init();work();return 0;
}