#include <bits/stdc++.h>
using namespace std;
int k, a[25], n, m, MIN;
int main() {
  cin >> k;
  for (int i = 0; i < k; i++) {
    cin >> a[i];
    if (a[i] > n) n = a[i];
  }
  if (n > 25)
    cout << n - 25;
  else
    cout << 0;
}
