#include <stdio.h>

int f1 (int x, int y) {
  if (x == 1 || y == 1) 
    return 0;
  else 
    return f1(x-1,y) + f1(x,y-1) + x*y;
}

int main() {
  int n, m;

  printf("Digite n e m: ");
  scanf("%d %d", &n, &m);
  printf("\nf(%d,%d) = %d\n", n, m, f1(n,m));
  return 0;
}