```cpp
#include<cstdio>
#include<cmath>
int main()
{
int n,a,b,sum;
int ans=10000000;
scanf("%d",&n);
for (int i=1;i<=3;i++)
{
scanf("%d %d",&a,&b);
sum=ceil(n*1.0/a)*b;
if (sum<ans) ans=sum;
}
printf("%d",ans);
}
```
by 金陈炫 @ 2017-10-24 17:14:32