Untitled

#include <iostream>

using namespace std;

int main() {
	unsigned long long A = 0;
	cin >> A;
	int b = 0;

	if (A >= 15) {
		A /= 10;
		b = A + 1;
		A *= b;
		cout << A << 25;
	}
	else {
		A *= A;
		cout << A;
	}
}