#include <bits/stdc++.h>
using namespace std;
bool isPrime(long long n) {
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  for (long long i = 5; i * i <= n; i = i + 6)
    if (n % i == 0 || n % (i + 2) == 0) return false;
  return true;
}
vector<long long> primes;
bool prime[10005];
void seive() {
  memset(prime, 1, sizeof(prime));
  prime[0] = 0;
  prime[1] = 0;
  for (long long i = 2; i <= 10000; i++) {
    if (prime[i] == 1) {
      for (long long j = i * i; j <= 10000; j += i) prime[j] = 0;
    }
  }
}
long long power(long long a, long long b) {
  long long ans = 1;
  while (b > 0) {
    if (b % 2 == 1) ans = (ans % 1000000007 * a % 1000000007) % 1000000007;
    a = (a * a) % 1000000007;
    b = b / 2;
  }
  return ans;
}
template <typename T>
std::string NumberToString(T Number) {
  std::ostringstream ss;
  ss << Number;
  return ss.str();
}
void solve() {
  long long n;
  cin >> n;
  long long a[n], i, j;
  for (i = 0; i < n; i++) cin >> a[i];
  long long m;
  cin >> m;
  long long b[m];
  for (i = 0; i < m; i++) cin >> b[i];
  sort(a, a + n);
  sort(b, b + m);
  long long ans = INT_MIN, ans1, ans2;
  for (i = 0; i < n; i++) {
    long long val = a[i];
    long long low = lower_bound(b, b + m, val) - b;
    long long score2 = 2 * low + (m - low) * 3;
    long long score1 = 2 * i + 3 * (n - i);
    long long diff = score1 - score2;
    if (diff > ans) {
      ans = diff;
      ans1 = score1;
      ans2 = score2;
    }
  }
  if ((n - m) * 2 > ans) {
    ans = (n - m) * 2;
    ans1 = n * 2;
    ans2 = m * 2;
  }
  cout << ans1 << ":" << ans2;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  bool codechef = 0;
  long long t = 1;
  if (codechef) cin >> t;
  while (t--) {
    solve();
  }
  return 0;
}
