#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pii pair<int,int>
#define fi first
#define se second
#define pb push_back
#define mp make_pair
const int nax = 3e5;
int n, q;
int tree[4*nax+5];
int s[nax+5];
int mn[nax+5]; //mulai nyala kapan
int merge(int a, int b) {
return max(a,b);
}
void build(int idx, int l, int r) {
if(r==l) {
tree[idx] = mn[l];
//cerr << l << " " << tree[idx] << endl ;
}
else {
int m = l+r >> 1;
build(idx<<1,l,m);
build(idx<<1|1, m+1, r);
tree[idx] = merge(tree[idx<<1], tree[idx<<1|1]);
}
}
void upd(int idx, int l, int r, int where, int val) {
if(r==l) tree[idx] = val;
else if (l <= where && where <= r) {
int m = l+r >> 1;
upd(idx<<1, l, m, where, val);
upd(idx<<1|1, m+1, r, where, val);
tree[idx] = merge(tree[idx<<1], tree[idx<<1|1]);
}
}
int rmq(int idx, int l, int r, int from, int to) {
if(to < l || from > r) return -1;
else if(from <= l && r <= to) {
//cerr << l << " " << r << " returns " << tree[idx] << endl;
return tree[idx];
}
else {
int m = l+r >> 1;
int ret = merge(rmq(idx<<1,l,m,from,to), rmq(idx<<1|1,m+1,r,from,to));
//cerr << l << " " << r << " returns " << ret << endl;
return ret;
}
}
signed main () {
scanf("%d %d", &n,&q);
for(int i=1; i<=n; i++) {
int x;
scanf("%1d", &x);
s[i] = x;
if(s[i]) mn[i] = 0;
else mn[i] = q+1000;
}
build(1, 1, n);
for(int t=1; t<=q; t++) {
string ts; cin >> ts;
if(ts == "query") {
int a, b; scanf("%d %d", &a, &b);
int ans = rmq(1, 1, n, a, b-1);
//cerr << ans << endl;
if(ans > q) ans = 0;
else ans = t-ans;
printf("%d\n", ans);
} else {
int x; scanf("%d", &x);
upd(1, 1, n, x, t);
}
}
}
