문제
풀이
#include <iostream>
using namespace std;
void solve(void) {
int m; cin >> m;
cout << (m < 30 ? m / 2 : 15 + (m - 30) * 3 / 2) << "." << (m & 1) * 5;
}
int main(void) {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}