#499 Numarare5

#include <iostream>

using namespace std;

int v[201];

int sumacif(int m)

{

   int s=0;

   while (m!=0)

   {

       s=s+m%10; m=m/10;

   }

   return s;

}

int main()

{

   int n, i, j, k=0;

   cin >> n;

   for (i=1; i<=n; ++i) cin >> v[i];

   for (i=1; i<n; ++i)

       for (j=i+1; j<=n; ++j)

           if (sumacif(v[i])==sumacif(v[j])) ++k;

   cout << k;

   return 0;

}