#include <bits/stdc++.h>
using namespace std;
int nor[200100 * 2], n, t, m, a[200100], b[200100], sola, solb, sol, pcta, pctb;
int main() {
  cin >> n;
  nor[++t] = 0;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
    nor[++t] = a[i];
  }
  cin >> m;
  for (int i = 1; i <= m; ++i) {
    cin >> b[i];
    nor[++t] = b[i];
  }
  sort(nor + 1, nor + t + 1);
  sort(a + 1, a + n + 1);
  sort(b + 1, b + m + 1);
  nor[++t] = max(a[n], b[n]) + 1;
  sol = -(1 << 30);
  for (int i = 1; i <= t; ++i) {
    int mij;
    int st = 1, dr = n;
    while (st <= dr) {
      mij = (st + dr) >> 1;
      if (a[mij] <= nor[i])
        st = mij + 1;
      else
        dr = mij - 1;
    }
    pcta = (st - 1) * 2 + (n - (st - 1)) * 3;
    st = 1, dr = m;
    while (st <= dr) {
      mij = (st + dr) >> 1;
      if (b[mij] <= nor[i])
        st = mij + 1;
      else
        dr = mij - 1;
    }
    pctb = (st - 1) * 2 + (m - (st - 1)) * 3;
    if (pcta - pctb > sol) {
      sol = pcta - pctb;
      sola = pcta;
      solb = pctb;
    } else if (pcta - pctb == sol && pcta > sola) {
      sola = pcta;
      solb = pctb;
    }
  }
  cout << sola << ":" << solb;
  return 0;
}
