#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <cstring>

typedef long long ll;
using namespace std;

#define mod 1000003
#define INF 10000000
#define LLINF 2000000000000000000LL

#define SIZE 10000

int bit_count(int n){
    int ret =0;
    
    while(n){
        if(n%2)
            ret++;
        
        n/=2;
    }
    
    return ret;
}

int main(){
    int n,a[10],m,b[10],ans=INF;
    
    scanf("%d",&n);
    
    for(int i=0;i<n;i++)
        scanf("%d",&a[i]);
    
    scanf("%d",&m);
    
    for(int i=0;i<m;i++)
        scanf("%d",&b[i]);
    
    sort(a,a+n);
    sort(b,b+m);
    
    do{
        int s=0,sum,cc=0;
        
        for(int i=m-1;i>=0;i--){
            sum=0;
            for(;s<n;s++){
                if(b[i]<sum+a[s]){
                    break;
                }
                sum+=a[s];
            }
            
            if(sum>0) cc++;
            
            if(s==n){
                ans = min(ans,cc);
                break;
            }
        }
        
        
    }while(next_permutation(a,a+n));
    
    printf("%d\n",(ans==INF ? -1 : ans));
    
    return 0;
}