#include<bits/stdc++.h>
using namespace std;
#define IOS {cin.tie(0);cout.tie(0);ios::sync_with_stdio(0);}
#define rep(i,l,r) for(int i=(l); i<=(r); i++)
#define per(i,r,l) for(int i=(r); i>=(l); i--)
#define ll long long
#define ilr int i,int l,int r
#define ls i<<1,l,mid
#define rs i<<1|1,mid+1,r
#define mi int mid=(l+r)/2;
const int N=2e5+5;
int n,Q;
ll s0[N<<2][2],s1[N<<2][2]; int tg[N<<2];
char s[N];
void bu(ilr){
    tg[i]=0; rep(j,0,1)s1[i][j]=0,s0[i][j]=0;
    if(l==r){
        s0[i][s[l]]=1; s1[i][s[l]]=l; 
        return;
    }
    mi
    bu(ls); bu(rs);
    rep(j,0,1)s0[i][j]=s0[i<<1][j]+s0[i<<1|1][j],s1[i][j]=s1[i<<1][j]+s1[i<<1|1][j];
}
void pd(int i){
    int li=i<<1,ri=li|1;
    swap(s0[li][0],s0[li][1]); swap(s1[li][0],s1[li][1]); tg[li]^=1;
    swap(s0[ri][0],s0[ri][1]); swap(s1[ri][0],s1[ri][1]); tg[ri]^=1;
    tg[i]=0;
}
void ud(ilr,int x,int y){
    if(l>=x && r<=y){
        tg[i]^=1; swap(s0[i][0],s0[i][1]); swap(s1[i][0],s1[i][1]); return;
    }
    if(tg[i])pd(i);
    mi
    if(mid>=x)ud(ls,x,y);
    if(y>mid)ud(rs,x,y);
    rep(j,0,1)s0[i][j]=s0[i<<1][j]+s0[i<<1|1][j],s1[i][j]=s1[i<<1][j]+s1[i<<1|1][j];
}
ll qu(ilr,int x,int y,int j){
    if(l>=x && r<=y)return s1[i][j];
    if(tg[i])pd(i);
    mi ll res=0;
    if(mid>=x)res+=qu(ls,x,y,j);
    if(y>mid)res+=qu(rs,x,y,j);
    return res;
}
int qu0(ilr,int x){
    if(l==r)return s0[i][1];
    if(tg[i])pd(i);
    mi
    if(mid>=x)return qu0(ls,x);
    return qu0(rs,x);
}
void slv(){
    string S;cin>>S; rep(i,1,n)s[i]=S[i-1]-'0';
    bu(1,1,n);
    while(Q--){
        int l,r; cin>>l>>r; ud(1,1,n,l,r);
        int X=s0[1][1];
        // cout<<X<<"eafaefa"<<endl;
        if(!X){
            cout<<"0\n";continue;
        }
        ll v0=0,v1=0,ans=0;
        if(X>1)v0=qu(1,1,n,1,X-1,0);
        if(X<n)v1=qu(1,1,n,X+1,n,1);
        ans=2*(v1-v0);
        if(qu0(1,1,n,X))ans+=X;
        else ans-=X;
        cout<<ans<<"\n";
    }
}
signed main(){
    IOS
    while(cin>>n>>Q){
        slv();
    }
}
/*
4 1
0010
4 4

3 2
010
1 2
2 3

5 1
00000
1 5
*/