Mine

void TForm1::Skaiciuoti()
{
 sum = 0; sand = 0;
 for(int i = 0; i < n; i++)
  for(int j = 0; j < m; j++)
   if(A[i][j] < 0)
    sum +=A[i][j];
   else
    sand = sand * A[i][j];
}