#include<cstdio>
#include<cmath>
#define N 300010
#define M 500010
using namespace std;
typedef unsigned long long ll;
const ll inf=1ULL<<63;
const double A=0.8;
ll tl[N],tr[N],tm[N];
int size[N],son[N][2],f[N],v[N],tot,root,id[N],cnt;
char s[N],ch;
inline void read(int&a){char c;while(!(((c=getchar())>='0')&&(c<='9')));a=c-'0';while(((c=getchar())>='0')&&(c<='9'))(a*=10)+=c-'0';}
inline bool cmp(int a,int b){return s[a]==s[b]?tm[a-1]>tm[b-1]:s[a]>s[b];}
int ins(int x,int p){int b=cmp(p,v[x]);if(!son[x][b]){son[x][b]=++tot;f[tot]=x;v[tot]=p;if(!b)tl[tot]=tl[x],tr[tot]=tm[x];else tl[tot]=tm[x],tr[tot]=tr[x];tm[tot]=(tl[tot]+tr[tot])>>1;return tot;}else return ins(son[x][b],p);
}
void dfs(int x){if(son[x][0])dfs(son[x][0]);id[++cnt]=x;if(son[x][1])dfs(son[x][1]);
}
int build(int fa,int l,int r,ll a,ll b){int mid=(l+r)>>1,x=id[mid];f[x]=fa;son[x][0]=son[x][1]=0;size[x]=1;tl[x]=a;tr[x]=b;tm[x]=(a+b)>>1;if(l==r)return x;if(l<mid)size[x]+=size[son[x][0]=build(x,l,mid-1,a,tm[x])];if(r>mid)size[x]+=size[son[x][1]=build(x,mid+1,r,tm[x],b)];return x;
}
inline int rebuild(int x){cnt=0;dfs(x);return build(f[x],1,cnt,tl[x],tr[x]);
}
inline void insert(int p){if(!root){root=tot=size[1]=1;v[1]=p;tr[1]=inf,tm[1]=inf>>1;return;}int x=ins(root,p);int deep=0,z=x;while(z)size[z]++,z=f[z],deep++;if(deep<log(tot)/log(1/A))return;while((double)size[son[x][0]]<A*size[x]&&(double)size[son[x][1]]<A*size[x])x=f[x];if(!x)return;if(x==root){root=rebuild(x);return;}int y=f[x],b=son[y][1]==x,now=rebuild(x);son[y][b]=now;
}
int l[M<<1],r[M<<1],min[M<<1],seq[M],TOT;
void build(int a,int b){int x=++TOT;if(a==b){min[x]=a;return;}int mid=(a+b)>>1;l[x]=TOT+1;build(a,mid);r[x]=TOT+1;build(mid+1,b);min[x]=tm[seq[min[l[x]]]]<=tm[seq[min[r[x]]]]?min[l[x]]:min[r[x]];
}
void change(int x,int a,int b,int c){if(a==b)return;int mid=(a+b)>>1;if(c<=mid)change(l[x],a,mid,c);else change(r[x],mid+1,b,c);min[x]=tm[seq[min[l[x]]]]<=tm[seq[min[r[x]]]]?min[l[x]]:min[r[x]];
}
int ask(int x,int a,int b,int c,int d){if(c<=a&&b<=d)return min[x];int mid=(a+b)>>1,i,j;if(d<=mid)return ask(l[x],a,mid,c,d);if(c>mid)return ask(r[x],mid+1,b,c,d);i=ask(l[x],a,mid,c,d),j=ask(r[x],mid+1,b,c,d);return tm[seq[i]]<=tm[seq[j]]?i:j;
}
int n,m,i,x,y,len,type,ans;
int main(){read(n);read(m);read(len);read(type);for(getchar(),i=1;i<=len;i++)s[len-i+1]=getchar();for(i=1;i<=len;i++)insert(i);for(i=1;i<=n;i++)read(seq[i]);build(1,n);while(m--){while(!(((ch=getchar())=='I')||(ch=='C')||(ch=='Q')));read(x);if(ch=='I')s[++len]=(x^ans*type)+'a',insert(len);if(ch=='C')read(seq[x]),change(1,1,n,x);if(ch=='Q')read(y),printf("%d\n",ans=ask(1,1,n,x,y));}return 0;
}