Untitled

#include <iostream>
using namespace std;

int main(){

	double a;

	long long result = 0;
	
	cin >> a;
	if (a == 5) {
		result += 25;
	}
	else {
		double new_a =(int)a / 10;
		result = new_a * (new_a + 1) * 100 + 25;
	}

	cout << result;


}