#include<iostream>
#include<fstream>
using namespace std;
const int PMAX=18,NMAX=250001;

int main()
{

    long n,m,q,p;
    int v[250000],i,j;
    ifstream fin("stramosi.in");
    ofstream fout("stramosi.out");
    fin>>n;
    fin>>m;
    for(i=0;i<n;i++)
       fin>>v[i];
    for(j=0;j<m*m;j++)
    {
        fin>>q;
        fin>>p;
        if(v[q]!=0&&p>=v[q])
        {
            if(p==1)
               fout<<v[q]<<" "<<endl;
            else
               fout<<v[q]-p<<" "<<endl;
        }
        else
            fout<<0<<endl;
        return 0;

    }





    return 0;
}