#include <bits/stdc++.h>
using namespace std;
const int mod = 99999997;
const int mmax = 200010;
const double eps = 1e-8;
const double pi = acos(-1.0);
const int inf = 0x3fffffff;
int a[200010], b[200010];
int main() {
  int n, m, sa, sb;
  int cnt1, cnt2, df;
  while (cin >> n) {
    for (int i = 0; i < n; i++) scanf("%d", &a[i]);
    cin >> m;
    for (int i = 0; i < m; i++) scanf("%d", &b[i]);
    sort(a, a + n);
    sort(b, b + m);
    sa = 3 * n, sb = 3 * m;
    df = sa - sb;
    cnt1 = 0, cnt2 = 0;
    while (cnt1 < n && cnt2 < m) {
      if (a[cnt1] == b[cnt2])
        cnt1++, cnt2++;
      else if (a[cnt1] < b[cnt2]) {
        df -= 1;
        cnt1++;
      } else {
        df += 1;
        if (df > sa - sb) {
          sa = 2 * cnt1 + 3 * (n - cnt1);
          sb = 2 * (cnt2 + 1) + 3 * (m - cnt2 - 1);
        }
        cnt2++;
      }
    }
    if (2 * n - 2 * m > sa - sb) sa = 2 * n, sb = 2 * m;
    cout << sa << ":" << sb << endl;
  }
  return 0;
}
