#include <stdio.h>

int main(void)
{
  int m, n, s;
  int i;
  scanf("%d", &m);

  s = 0;
  for(i = 0; i < m * (m - 1) / 2; i++){
    scanf("%d", &n);
    s += n;
   }

   printf("%d\n", s / (m - 1));

   return (0);
}