#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<climits>
#include<cmath>
#include<string>
#include<sstream>
#include<vector>
#include<list>
#include<deque>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<algorithm>
#include<iterator>
#include<numeric>
#include<fstream>

#define FORF(i,a,b) for(int i=a; i<=b; ++i)
#define FORB(i,a,b) for(int i=a; i>=b; --i)
#define ALL(v) v.begin(),v.end()
#define min3(a,b,c) min(min(a,b),c)
#define SIZE 400010
#define MAXN 3000000

using namespace std;


typedef long long LL;


struct basket
{
    int team;
    LL dist;

    friend bool operator<(basket b1,basket b2)
    {
        return b1.dist<b2.dist;
    }
};

int N,M;
int cnt1,cnt2;
LL scA,scB,cuA,cuB;


int main()
{
    basket bsk[SIZE];

    scanf("%d",&N);
    FORF(i,0,N-1)
    {
        scanf("%I64d",&bsk[i].dist);
        bsk[i].team=1;
    }

    scanf("%d",&M);
    FORF(i,0,M-1)
    {
        scanf("%I64d",&bsk[i+N].dist);
        bsk[i+N].team=2;
    }


    sort(bsk,bsk+N+M);


    scA=3*N;
    scB=3*M;
    FORF(i,0,N+M-1)
    {
        if(bsk[i].team==1)
            ++cnt1;
        else
            ++cnt2;


        cuA=2*cnt1 + 3*(N-cnt1);
        cuB=2*cnt2 + 3*(M-cnt2);


        if(cuA-cuB>scA-scB || (cuA-cuB==scA-scB && cuA>scA))
        {
            scA=cuA;
            scB=cuB;
        }
    }


    printf("%I64d:%I64d\n",scA,scB);


    return 0;
}