#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("stramosi.in");
ofstream fout("stramosi.out");
int a[250000],x,y,t,n,m,b[250000],k=0;
int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        fin>>t;
        if(t!=0)
            {a[i]=i-t-1+a[t];
             b[i]=k;}
        else
            {
                k++;
                b[i]=k;
                a[i]=0;}
    }
    for(int j=1;j<=m;j++)
    {
        fin>>x>>y;
        if(x<y)
            fout<<0<<"\n";
        else if(y==1)
            fout<<x-1<<"\n";
        else if(b[x]!=b[x-y-a[x]])
            fout<<0<<"\n";
        else
            fout<<x-y-a[x]<<"\n";
    }
    return 0;
}