#include<bits/stdc++.h> using namespace std; int main(){ int n,s1,s2,s3,b1,b2,b3,a,b,c,min; cin>>n>>s1>>b1>>s2>>b2>>s3>>b3; a=ceil(n*1.0/s1)*b1; b=ceil(n*1.0/s2)*b2; c=ceil(n*1.0/s3)*b3; min=a; if(b<min){ min=b; } if(c<min){ min=c; } cout<<min; return 0; }