#include <bits/stdc++.h>
using namespace std;

#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

#define ll long long
#define ld long double
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define FOR(i,l,r) for(int i=(l);i<=(r);i++)
#define ROF(i,r,l) for(int i=(r);i>=(l);i--)
int inf=1000000007;
ll infl=1000000000000000007;
ll mod=1000000007;

const int N=300007;

bool is[N];
int ans[N];
vector<pair<pair<int,int>,int>>add[N];

signed main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	string s;
	int n,q;
	cin>>n>>q>>s;
	set<pair<pair<int,int>,int>>S;
	int it=1;
	FOR(i,1,n)
	{
		is[i]=s[i-1]-'0';
		if(s[i-1]=='0')
		{
			if(it<i)
			{
				S.insert({{it,i-1},0});
				it=i+1;
			}
		}
	}
	S.insert({{-inf,-inf},0});
	S.insert({{inf,inf},0});
	if(it<=n) S.insert({{it,n},0});
	debug(S);
	FOR(i,1,q)
	{
		string tt;
		cin>>tt;
		if(tt[0]=='t')
		{
			int x;
			cin>>x;
			if(is[x])
			{
				pair<pair<int,int>,int>t=*--S.upper_bound({{x,inf},inf});
				add[i].pb({t.st,i-t.nd});
				S.erase(t);
				if(t.st.st<x) S.insert({{t.st.st,x-1},i});
				if(t.st.nd>x) S.insert({{x+1,t.st.nd},i});
			}
			else
			{
				int L=x,R=x;
				if(is[x-1])
				{
					pair<pair<int,int>,int>t=*--S.upper_bound({{x-1,inf},inf});
					L=t.st.st;
					add[i].pb({t.st,i-t.nd});
					S.erase(t);
				}
				if(is[x+1])
				{
					pair<pair<int,int>,int>t=*--S.upper_bound({{x+1,inf},inf});
					R=t.st.nd;
					add[i].pb({t.st,i-t.nd});
					S.erase(t);
				}
				S.insert({{L,R},i});
			}
			is[x]^=1;
			ans[i]=-1;
		}
		else
		{
			int l,r;
			cin>>l>>r;
			r--;
			pair<pair<int,int>,int>t=*--S.upper_bound({{l,inf},inf});
			if(t.st.st<=l&&t.st.nd>=r) ans[i]=i-t.nd;
			FOR(j,1,i-1)
			{
				debug(j,add[j]);
				for(auto [p,c]:add[j]) if(p.st<=l&&p.nd>=r) ans[i]+=c; 
			}
		}
	}
	FOR(i,1,q) if(ans[i]>=0) cout<<ans[i]<<endl;
	return 0;
}