#include <bits/stdc++.h>
int main() {
  int i, n, x, s = 0, max = 0;
  scanf("%d", &n);
  for (i = 0; i < n; i++) {
    scanf("%d", &x);
    if (x > max) max = x;
    s += x;
  }
  printf("%d", n * max - s);
  return 0;
}
