#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include <cmath>

 #include<stack>

 #include<vector>

 #include<map>

 #include<set>

 #include<queue>

 #include<algorithm>

 using namespace std;

 typedef long long LL;

 const int INF = (<<)-;

 const int mod=;

 const int maxn=;

 int n,m;

 int a[maxn],b[maxn],c[maxn];

 int main(){

     int cnt=;

     c[++cnt]=;

     scanf("%d",&n);

     for(int i=;i<n;i++) scanf("%d",&a[i]),c[++cnt]=a[i];

     scanf("%d",&m);

     for(int i=;i<m;i++) scanf("%d",&b[i]),c[++cnt]=b[i];

     sort(a,a+n);

     sort(b,b+m);

     sort(c,c+cnt);

     int tmp=-INF,L,R;

     int lb,ub;

     for(int i=;i<=cnt;i++){

         int x=upper_bound(a,a+n,c[i]) - a;

         int y=upper_bound(b,b+m,c[i]) - b;

         lb = x* + (n-x)*;

         ub = y* + (m-y)*;

         if(lb - ub > tmp){

             tmp=lb-ub;

             L=lb;R=ub;

         }

         if(lb - ub == tmp && lb > L) L = lb;

     }

     printf("%d:%d\n",L,R);

     return ;

 }