#include <bits/stdc++.h>
int main() {
  int a[25];
  int K, r, size = 0;
  scanf("%d", &K);
  for (int i = 0; i < K; ++i) {
    scanf("%d", &r);
    if (r > 25) {
      a[size++] = r;
    }
  }
  for (int i = 0; i < size; ++i) {
    for (int j = i + 1; j < size; ++j) {
      if (a[i] > a[j]) {
        int temp = a[i];
        a[i] = a[j];
        a[j] = temp;
      }
    }
  }
  int ans = size;
  for (int i = 0; i < size; ++i) {
    if (i == 0) {
      ans += a[i] - 25 - 1;
    } else {
      ans += a[i] - a[i - 1] - 1;
    }
  }
  printf("%d\n", ans);
  return 0;
}
