#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("stramosi.in");
ofstream fout("stramosi.out");
int x,y,t,n,m,k=0;
struct element
{
    int v,r;
}a[250002];
int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;++i)
    {
        fin>>t;
        if(t!=0)
            {a[i].v=i-t-1+a[t].v;
             a[i].r=k;}
        else
            {
                k++;
                a[i].r=k;
                a[i].v=0;}
    }
    for(int j=1;j<=m;++j)
    {
        fin>>x>>y;
        if(x<y||x==y)
            fout<<0<<"\n";
        else if(y==1)
            fout<<x-1<<"\n";
        else if(a[x].r!=a[x-y-a[x].v].r)
            fout<<0<<"\n";
        else
            fout<<x-y-a[x].v<<"\n";
    }
    return 0;
}