代码↓

#include <bits/stdc++.h>
using namespace std;
double mins = INT_MAX,t,a,c,s;
int main(){
	cin>>t;
	for(int i = 0 ; i < 3 ; i ++){
		cin>>a>>c;
		s = ceil(t / a) * c;
		mins = min(mins,s); 
	}
	cout<<mins;
}