158B - Taxi

#include <iostream>
using namespace std;

int main()
{
    int n, i, m = 0;
    int p[5] = { 0 };
    cin >> n;
    cout << endl;
    for (i = 0; i < n; i++)
    {
        cin >> m;
        p[m]++;
    }

    cout << endl;
    for (i = 1; i <= 4; i++)
    {
        cout << p[i] << endl;
    }
    cout << endl;

    if (p[3] >= p[1])
    {
        if (p[2] % 2 == 0)
        {
            cout << (p[4] + p[3] + p[2] / 2) << endl;
        }
        else
        {
            cout << (p[4] + p[3] + p[2] / 2 + 1) << endl;
        }
    }
    else
    {
        if (((p[1] - p[3]) + p[2] * 2) % 4 == 0)
        {
            cout << (p[4] + p[3] + ((p[1] - p[3]) + p[2] * 2) / 4) << endl;
        }
        else
        {
            cout << (p[4] + p[3] + ((p[1] - p[3]) + p[2] * 2) / 4 + 1) << endl;
        }
    }
    system("pause");
}