计算 + ceil（改了三会啊）

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;//the amount of pencils
    double a,b,c,d,e,f;//a,b,c refers to the amount of the pencils in the pocket
    //d,e,f refers to the price of the kind of a pocket
    cin>>a>>d>>b>>e>>c>>f;
    double p1,p2,p3;
    p1=ceil(n/a)*d;
    p2=ceil(n/b)*e;
    p3=ceil(n/c)*f;
    cout<<int(min(min(p1,p2),p3));//cout the min price of the three boxes
    return 0;
}