#include<bits/stdc++.h>
#define ll long long
#define N 200005

int n,q;
char s[N];

struct node{
	ll s0,s1;
	int c0,c1;
	bool rev;
	node(){
		s0=s1=c0=c1=rev=0;
	}
}t[N<<2];
node operator + (node x,node y){
	node res;
	res.s0=x.s0+y.s0,res.s1=x.s1+y.s1;
	res.c0=x.c0+y.c0,res.c1=x.c1+y.c1;
	return res;
}
inline void psh(int p){
	t[p].rev^=1;
	std::swap(t[p].s0,t[p].s1),std::swap(t[p].c0,t[p].c1);
}
inline void pshd(int p){
	if(t[p].rev)
		psh(p<<1),psh(p<<1|1);
	t[p].rev=0;
}
inline void build(int p,int L,int R){
	t[p]=node();
	if(L==R){
		if(s[L]=='0')
			t[p].s0=L,t[p].c0=1;
		else
			t[p].s1=L,t[p].c1=1;
		return;
	}
	int mid=(L+R)>>1;
	build(p<<1,L,mid),build(p<<1|1,mid+1,R);
	t[p]=t[p<<1]+t[p<<1|1];
}
inline void rev(int p,int L,int R,int l,int r){
	if(L>r||R<l)
		return;
	if(l<=L&&R<=r)
		return psh(p);
	pshd(p);
	int mid=(L+R)>>1;
	rev(p<<1,L,mid,l,r),rev(p<<1|1,mid+1,R,l,r);
	t[p]=t[p<<1]+t[p<<1|1];
}
inline node sum(int p,int L,int R,int l,int r){
	if(L>r||R<l)
		return node();
	if(l<=L&&R<=r)
		return t[p];
	pshd(p);
	int mid=(L+R)>>1;
	return sum(p<<1,L,mid,l,r)+sum(p<<1|1,mid+1,R,l,r);
}

int main(){
	while(~scanf("%d%d%s",&n,&q,s+1)){
		build(1,1,n);
		while(q--){
			int l,r;
			scanf("%d%d",&l,&r);
			rev(1,1,n,l,r);
			int k=t[1].c1;
			node tmp=sum(1,1,n,k,k);
			printf("%lld\n",-2*sum(1,1,n,1,k-1).s0+2*sum(1,1,n,k+1,n).s1+(tmp.c0?-k:k));
		}
	}
}