[NOIP 2016 普及组] 买铅笔

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    int minn=0x3f3f3f3f;
    for(int i=1;i<=3;i++){
        int a,b;
        cin>>a>>b;
        int t=(n-1)/a+1;
        minn=min(minn,t*b);
    }
    cout<<minn;
    return 0;
}