#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
double sqr(double a) { return a * a; }
struct point {
  int x, y;
};
long long a[1000010];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, mx = 0, ans = 0;
  cin >> n;
  for (long long i = 0; i < n; i++) {
    long long x;
    cin >> x;
    mx = max(mx, x);
    a[x] = 1;
  }
  if (n < 25) {
    long long x = 25 - n;
    long long i = 1;
    while (x && i <= 25) {
      if (!a[i]) {
        x--;
        a[i] = 1;
      }
      i++;
    }
  }
  for (long long i = 1; i <= mx; i++) {
    if (!a[i]) ans++;
  }
  cout << ans << endl;
  getchar();
  getchar();
  return 0;
}
