#include<bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
#define mp make_pair
#define f first
#define s second
using namespace std;
const int mxn=3e5+5;
const int inf=1e9;
int a[mxn];
int ans[mxn] = {};
int n;
struct BIT
{
int bit[mxn] = {};
void update(int p,int v) {
if(p==0) return;
for(;p< mxn; p+= p&-p) bit[p] += v;
}
int query(int p) {
int r=0;
for(;p>0;p-=p&-p) r += bit[p];
return r;
}
int query(int a,int b) {
return query(b) - query(a - 1);
}
} bt1,bt2;
struct QUERY {
int l,r,ind,i;
int val;
QUERY(int a = 0,int b = 0,int c = 0,int d = -1 ,int v = 0) : l(a),r(b),ind(c),i(d),val(v) {}
};
vector<QUERY> Qs;
void process(vector<int> left,vector<int> right) {
vector<pair<pii,int>> v;
for(int i : left) {
v.push_back(mp(mp(Qs[i].l,-1),i));
v.push_back(mp(mp(Qs[i].i,2),i));
}
for(int i : right) {
v.push_back(mp(mp(Qs[i].l,0),i));
//v.emplace_back(right[i].r,1,i);
}
sort(v.begin(),v.end());
int cursum = 0;
for(auto i : v) {
if(i.f.s == -1) {
cursum += Qs[i.s].val;
bt1.update(Qs[i.s].r,Qs[i.s].val);
bt2.update(Qs[i.s].i,Qs[i.s].val);
}
if(i.f.s == 2) {
cursum -= Qs[i.s].val;
bt1.update(Qs[i.s].r,-Qs[i.s].val);
bt2.update(Qs[i.s].i,-Qs[i.s].val);
}
if(i.f.s == 0) {
int x = bt1.query(Qs[i.s].r - 1);
int y = bt2.query(mxn - 1) - bt2.query(Qs[i.s].r);
ans[Qs[i.s].ind] += cursum - x - y;
}
}
}
void solve(int l,int r) {
if(l == r) return;
int mid = l + r >> 1;
vector<int> left,right;
for(int i = l; i <= mid; i++) {
if(Qs[i].i != -1) {
left.push_back(i);
}
}
for(int i = mid + 1; i <= r; i++) {
if(Qs[i].i == -1) {
right.push_back(i);
}
}
process(left,right);
solve(l,mid);
solve(mid + 1,r);
}
int main() {
int k;
cin >> n >> k;
string s;
cin >> s;
for(int i = 1; i <= n; i++) {
a[i] = s[i - 1] - '0';
}
BIT cur;
for(int i = 1; i <= n; i++) {
if(a[i] == 1) cur.update(i,1);
}
char p[7];
for(int i = 1; i <= k; i++) {
scanf("%s",p);
if(p[0] == 't') {
int x;
scanf("%d",&x);
QUERY q;
if(a[x] == 0)
cur.update(x,1);
int lo = 1;
int hi = x;
while(lo <= hi) {
int mid = lo + hi >> 1;
if(cur.query(mid,x) == x - mid + 1) {
q.l = mid;
hi = mid - 1;
} else {
lo = mid + 1;
}
}
lo = x;
hi = n;
while(lo <= hi) {
int mid = lo + hi >> 1;
if(cur.query(x,mid) == mid - x + 1) {
q.r = mid;
lo = mid + 1;
} else {
hi = mid - 1;
}
}
q.ind = i;
q.i = x;
if(a[x] == 0) q.val = -i;
else q.val = i;
if(a[x] == 1) {
cur.update(x,-1);
}
a[x] ^= 1;
Qs.push_back(q);
} else {
int a,b;
scanf("%d%d",&a,&b);
b--;
Qs.push_back(QUERY(a,b,i));
if(cur.query(a,b) == b - a + 1) {
ans[i] = i;
}
}
}
solve(0,Qs.size() - 1);
for(int i = 0; i < Qs.size(); i++) {
if(Qs[i].i == -1) printf("%d\n",ans[Qs[i].ind]);
}
}
