#include <bits/stdc++.h>
using namespace std;
struct abc {
  long long int y, x;
};
bool compare(abc a1, abc a2) {
  if (a1.x == a2.x) return a1.y < a2.y;
  return a1.x < a2.x;
}
long long int countDivisors(long long int n) {
  long long int cnt = 0;
  for (long long int i = 1; i <= sqrt(n); i++) {
    if (n % i == 0) {
      if (n / i == i)
        cnt++;
      else
        cnt = cnt + 2;
    }
  }
  return cnt;
}
const long long int mod = 1e9 + 7;
long long int n, m, x, y, l, r, ans, k, q;
string second, p;
map<long long int, long long int> mp;
void solve() {
  cin >> n;
  long long int a[n];
  for (long long int i = 0; i < n; i++) cin >> a[i];
  cin >> m;
  long long int b[m];
  for (long long int i = 0; i < m; i++) cin >> b[i];
  sort(a, a + n);
  sort(b, b + m);
  long long int j = m - 1;
  long long int l = n * 2, x = n * 2, r = m * 2, y = m * 2;
  for (long long int i = n - 1; i >= 0; i--) {
    x++;
    while (j >= 0 && b[j] >= a[i]) {
      j--;
      y++;
    }
    if (x - y >= l - r) {
      l = x, r = y;
    }
  }
  cout << l << ':' << r;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  solve();
}
