문제
풀이
#include <iostream>
using namespace std;
void solve(void) {
int n, m, a, b; cin >> n >> m >> a >> b;
cout << (3 * n > m ? (3 * n - m) * a + b : 0);
}
int main(void) {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}