#include <bits/stdc++.h>
using namespace std;
int r[30];
int main() {
  int k, cnt = 0, ans = 0;
  cin >> k;
  for (int i = 0; i < k; i++) {
    cin >> r[i];
    if (r[i] <= 25) cnt++;
  }
  sort(r, r + k);
  ans += (k - cnt);
  ans = ans + (r[k - 1] - 25) - (k - cnt);
  if (ans < 0)
    cout << 0 << endl;
  else
    cout << ans << endl;
  return 0;
}
