#include<bits/stdc++.h>
#define reg register int
#define il inline
#define fi first
#define se second
#define mk(a,b) make_pair(a,b)
#define numb (ch^'0')
#define pb push_back
#define solid const auto &
#define enter cout<<endl
#define pii pair<int,int>
using namespace std;
typedef long long ll;
template<class T>il void rd(T &x){char ch;x=0;bool fl=false;while(!isdigit(ch=getchar()))(ch=='-')&&(fl=true);for(x=numb;isdigit(ch=getchar());x=x*10+numb);(fl==true)&&(x=-x);
}
template<class T>il void output(T x){if(x/10)output(x/10);putchar(x%10+'0');}
template<class T>il void ot(T x){if(x<0) putchar('-'),x=-x;output(x);putchar(' ');}
template<class T>il void prt(T a[],int st,int nd){for(reg i=st;i<=nd;++i) ot(a[i]);putchar('\n');}namespace Miracle{
const int N=500000+5;
const int M=1000000+5;
const double inf=1e18;
const double alp=0.75;
#define mid ((l+r)>>1)
#define Md ((L+R)/2.0)
int n,q,m,typ;
int pos[N];
char s[M];
int rt;
namespace SGT{
struct node{int ch[2];int sz;double l,r;double val;void init(double L,double R){sz=1;ch[0]=ch[1]=0;l=L;r=R;val=(L+R)/2;}
}t[M];
int tot;
#define ls t[x].ch[0]
#define rs t[x].ch[1]
void pushup(int x){if(!x) return;t[x].sz=t[ls].sz+t[rs].sz+1;
}
bool isbad(int x){return (t[ls].sz>t[x].sz*alp||t[rs].sz>t[x].sz*alp);
}
int q[M],num;
void dfs(int x){if(!x) return;dfs(ls);q[++num]=x;dfs(rs);
}
int build(int l,int r,double L,double R){if(l>r) return 0;int x=q[mid];t[x].init(L,R);ls=build(l,mid-1,L,Md);rs=build(mid+1,r,Md,R);pushup(x);return x;
}
void rebuild(int &x){num=0;dfs(x);x=build(1,num,t[x].l,t[x].r);
}
int sta[M],top;
void che(){for(reg i=1;i<=top;++i){if(isbad(sta[i])){if(i==1) rebuild(rt);else rebuild(t[sta[i-1]].ch[t[sta[i-1]].ch[1]==sta[i]]),pushup(sta[i-1]);return;}}
}
bool cmp(int x,int y){//x<y?if(s[x]!=s[y]) return s[x]<s[y];return t[x-1].val<t[y-1].val;
}
void ins(int p){//x is pos++tot;if(!rt){rt=tot;t[tot].init(1,inf);return;}int x=rt;top=0;while(1){int d=cmp(x,p);sta[++top]=x;++t[x].sz;if(!t[x].ch[d]){t[x].ch[d]=tot;if(d==1){//rson
                t[tot].init(t[x].val,t[x].r);}else{t[tot].init(t[x].l,t[x].val);}break;}x=t[x].ch[d];}che();
}
void pb(int x){ins(x);
}
#undef ls
#undef rs
}
namespace SMT{
#define ls (x<<1)
#define rs (x<<1|1)
struct node{int id;
}t[4*N];
int chm(int x,int y){return SGT::t[pos[x]].val<=SGT::t[pos[y]].val?x:y;
}
void pushup(int x){t[x].id=chm(t[ls].id,t[rs].id);
}
void build(int x,int l,int r){if(l==r){t[x].id=l;return;}build(ls,l,mid);build(rs,mid+1,r);pushup(x);
}
void upda(int x,int l,int r,int p){if(l==r){t[x].id=l;return;}if(p<=mid) upda(ls,l,mid,p);else upda(rs,mid+1,r,p);pushup(x);
}
int query(int x,int l,int r,int L,int R){if(L<=l&&r<=R){return t[x].id;}if(L>mid) return query(rs,mid+1,r,L,R);if(R<=mid) return query(ls,l,mid,L,R);return chm(query(ls,l,mid,L,R),query(rs,mid+1,r,L,R));
}}
int main(){rd(n);rd(q);rd(m);rd(typ);scanf("%s",s+1);reverse(s+1,s+m+1);for(reg i=1;i<=n;++i){rd(pos[i]);}for(reg i=1;i<=m;++i){SGT::pb(i);}SMT::build(1,1,n);char ch[233];int x,y;int lasans=0;while(q--){scanf("%s",ch);if(ch[0]=='I'){rd(x);if(typ) x=x^lasans;s[++m]='a'+x;SGT::pb(m);}else if(ch[0]=='C'){rd(x);rd(y);pos[x]=y;SMT::upda(1,1,n,x);}else if(ch[0]=='Q'){//warning!!!
            rd(x);rd(y);int now=SMT::query(1,1,n,x,y);lasans=now;printf("%d\n",lasans);//update lasans
        }}return 0;
}}
signed main(){Miracle::main();return 0;
}/*Author: *Miracle*
*/