#import <fstream>
std::fstream f("tricouri.in"), g("tricouri.out", std::_S_out);
int n, m, k, p, q, i, j, A[32][32][8], s;
void h(int k, int x, int i){if(i==p){s=k||s>=x||x%p?s:x;return;}h(k,x,i+1);for(int j=0;j<k;){if(!A[p][i][j])return;x+=A[p][i][j];h(k-j++-1,x,i+1);}}
main()
{f>>n>>m;for(q=0;q<n;q++){f>>j;for(i=2;p=j%i,i<21;A[i++][p][k]=j)
      for (k = 5; k && j > A[i][p][k - 1];)
        A[i][p][k--] = A[i][p][k-1];
      }
  for(q=0;q<m;q++)
  {
    f >> k >> p;
    s = -1;
    h(k, 0, 0);
    g << s << '\n';
  }
}