#include<iostream>
using namespace std;
int main(){
    int n,an,am,bn,bm,cn,cm;
    cin>>n>>an>>am>>bn>>bm>>cn>>cm;
    cout<<min(((n-1)/an+1)*am,min(((n-1)/bn+1)*bm,((n-1)/cn+1)*cm));}

欢迎提出更短代码