#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
const int INF = 0x3fffffff;
#define rep(n) for(int i=0;i<n;++i)
#define each(i,...) for(auto&& i:__VA_ARGS__)
#define all(i) begin(i),end(i)
#define Uniq(a) sort(all(a));a.erase(unique(all(a)),end(a))
template<class T, class U> bool chmin(T& a, const U& b){ if(a > b){ a = b; return 1; } return 0; }
template<class T, class U> bool chmax(T& a, const U& b){ if(a < b){ a = b; return 1; } return 0; }
struct Lazy{
int type;
int first, last, cnt;
void operator+=(const Lazy& b){ // toggle の合成
if(!type){
*this = b;
return;
}
cnt += b.cnt;
if(type == 2) cnt += b.first - last;
last = b.last;
type = b.type;
}
};
struct kdTree{
kdTree *l = nullptr, *r = nullptr;
Lazy val = {0, 0, 0, 0};
int xmin = INF, xmax = -INF, ymin = INF, ymax = -INF;
kdTree(vector<pii>::iterator from, vector<pii>::iterator to, bool divx = false){
for(auto p = from; p != to; p++){
auto& i = *p;
chmin(xmin, i.first);
chmax(xmax, i.first);
chmin(ymin, i.second);
chmax(ymax, i.second);
}
if(to - from == 1) return;
auto p = from + (to - from) / 2;
if(divx) nth_element(from, p, to, [](pii a, pii b){ return a.first < b.first; });
else nth_element(from, p, to, [](pii a, pii b){ return a.second < b.second; });
l = new kdTree(from, p, !divx);
r = new kdTree(p, to, !divx);
}
void push(){
if(!l) return;
if(!val.type) return;
l->val += val;
r->val += val;
val = {0, 0, 0, 0};
}
void query(int x1, int x2, int y1, int y2, const Lazy& x){ // [x1, x2] && [y1, y2]
if(xmax < x1 || x2 < xmin || ymax < y1 || y2 < ymin) return;
if(x1 <= xmin && xmax <= x2 && y1 <= ymin && ymax <= y2){ // <- ここだけバグらせやすいので注意
val += x;
return;
}
push();
l->query(x1, x2, y1, y2, x);
r->query(x1, x2, y1, y2, x);
}
int get(int x, int y, int time){ // l の範囲内 && r の範囲内 になることがあってこうなっているが、これは構築部分を変えれば回避できる
if(!l) return val.cnt + (val.type == 2 ? time - val.last : 0);
push();
if(l->xmin <= x && x <= l->xmax && l->ymin <= y && y <= l->ymax){
int ans = l->get(x, y, time);
if(ans != -1) return ans;
}
if(r->xmin <= x && x <= r->xmax && r->ymin <= y && y <= r->ymax){
return r->get(x, y, time);
}
return -1;
}
};
int main(){
cin.tie(nullptr);
ios::sync_with_stdio(false);
int n, q;
cin >> n >> q;
string s;
cin >> s;
vector<pii> a;
vector<pair<char, pii>> query(q);
each(i, query){
string s;
cin >> s;
i.first = s[0];
int x, y = 2;
cin >> x;
if(i.first == 'q') cin >> y;
x--; y -= 2;
i.second = {x, y};
if(i.first == 'q') a.emplace_back(x, y);
}
Uniq(a);
kdTree tree(all(a));
set<int> dark = {-1, n};
tree.query(0, n, 0, n, {2, 0, 0, 0});
rep(n) if(s[i] == '0'){
auto p = dark.insert(i).first;
int x1 = *prev(p) + 1, x2 = *next(p) - 1;
tree.query(x1, i, i, x2, {1, 0, 0, 0});
}
rep(q){
char c = query[i].first;
int x, y, time = i + 1;
tie(x, y) = query[i].second;
if(c == 't'){
s[x] ^= 1;
if(s[x] == '1'){
auto p = dark.find(x);
int x1 = *prev(p) + 1, x2 = *next(p) - 1;
tree.query(x1, x, x, x2, {2, time, time, 0});
dark.erase(p);
}
else{
auto p = dark.insert(x).first;
int x1 = *prev(p) + 1, x2 = *next(p) - 1;
tree.query(x1, x, x, x2, {1, time, time, 0});
}
}
else{
cout << tree.get(x, y, time) << '\n';
}
}
}
//https://hackmd.io/@tatyam-prime/street_lamps#
