#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int k;
  cin >> k;
  vector<int> finalists;
  for (int i{0}, a; i < k; ++i) {
    cin >> a;
    finalists.push_back(a);
  }
  sort(finalists.begin(), finalists.end());
  if (finalists[k - 1] <= 25)
    cout << 0;
  else
    cout << finalists[k - 1] - 25;
}
