#include<bits/stdc++.h>
#define MAXN 1000005
#define ll long long
#define inf 2000000
using namespace std;
int len[3],a[3][MAXN],c[MAXN],x[MAXN],seq[3][MAXN],bel[MAXN];
ll ta[3][MAXN];
int N,M,K,Q;

int bit(int x){return x&-x;}
void add(int k,int x,ll y){
    for (;x<=len[k]+1;x+=bit(x)){
//        printf("%d %d\n",x,bit(x));
        ta[k][x]+=y;
    }
//    printf("ok\n");
}
void modify(int k,int x) {
    if (a[k][x]>=inf){
        add(k,x,-inf);
        a[k][x]-=inf;
    }
    else{
        add(k,x,inf);
        a[k][x]+=inf;
    }
}
ll ask_0(int k,int x){
    if (x<=0) return 0;
    ll res=0;
    for(;x;x-=bit(x)) res+=ta[k][x];
    return res;
}
ll ask(int k,int x,int y) {
    return ask_0(k, y - 1) - ask_0(k, x - 1);
}

void query(int x,int y) {
    ll res = inf;
    int bx=bel[x],by=bel[y];
    int nx=seq[bx][x],ny=seq[by][y];
    if (bx==by) {
        res=min(res,ask(bx,nx,ny));
        res=min(res,ask(bx,1,nx)+ask(bx,ny,len[bx]+1)+min(ask((bx+1)%3,1,len[(bx+1)%3]),ask((bx+2)%3,1,len[(bx+2)%3])));
    } else {
        ll x1x=ask(bx,1,nx);
        ll y1y=ask(by,1,ny);
        ll xxn=ask(bx,nx,len[bx]+1);
        ll yyn=ask(by,ny,len[by]+1);
        res=min(res,x1x+y1y);
        res=min(res,xxn+yyn);
        int bz=3-bx-by;
        res=min(res,min(x1x+yyn,y1y+xxn)+ask(bz,1,len[bz]+1));
    }
    if (res>=inf) printf("impossible\n");
    else printf("%lld\n",res);
}

int main(){
    scanf("%d%d%d%d",&N,&K,&M,&Q);
    for (int i=1;i<=N;i++) scanf("%d",&c[i]);
    for (int i=1;i<=M+1;i++) scanf("%d",&x[i]);

    int now=1;
    len[0]=K-1;
    for (int i=1;i<K;i++){
        bel[now]=0;
        seq[0][now]=i;
        a[0][i]=c[i];
        now++;
    }
    bel[K]=0;
    seq[0][K]=K;

//    printf("1\n");

    now=1;
    len[1]=N-K+1;
    for (int i=1;i<=N-K+1;i++){
        bel[now]=1;
        seq[1][now]=i;
        a[1][i]=c[N-i+1];
        if (now==1) now=N; else now--;
    }
//    printf("2\n");

    now=1;
    len[2]=M+1;
    for (int i=1;i<=M+1;i++){
        bel[now]=2;
        seq[2][now]=i;
        a[2][i]=x[i];
        if (now==1) now=N+1; else now++;
    }
//    printf("3\n");
//    printf("%d %d %d\n",len[0],len[1],len[2]);

    for (int i=0;i<3;i++)
        for (int j=1;j<=len[i];j++) add(i,j,a[i][j]);
//    printf("?\n");

    while(Q--) {
        char s[10];
        int X,Y;
        scanf("%s", s);
        if (s[0] == 'q') {
            scanf("%d%d", &X, &Y);
            query(X, Y);
        } else {
            scanf("%d", &X);
            if (s[0] == 'x') modify(2, X + 1);
            else {
                if (X >= K) modify(1, N - X + 1);
                else modify(0, X);
            }
        }
    }
}