WA3个点，请大神指教 代码如下

#include<bits/stdc++.h>  
using namespace std;
long long s=0,s1=0; 
int a[100005],b[100005];
int main()
{
    int n,minn=100000;
    cin>>n;
    cin>>a[1]>>b[1]>>a[2]>>b[2]>>a[3]>>b[3];
    for(int i=1;i<=3;i++){
    	while(s1<n){
    		s1+=a[i];
    		s+=b[i];
    	}
    	if(s<minn)minn=s;
    	s=0;
    	s1=0;
    }
    cout<<minn<<endl;
    return 0;   
}