#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;

}