#include <iostream>
#include <vector>
using namespace std;
string f(long long k)
{
    if(k == 1)
    {
        return "4";
    }
    if(k == 2)
    {
        return "7";
    }
    long long s = 1;
    int d = 1;
    while (k > 2 * s)
    {
        k -= 2 * s;
        s *= 2;
        d++;
    }
    if (k <= s)
    {
        return "4" + f(k);
    }
    else
    {
        return "7" + f(k - s);
    }
}

int main()
{
    long long k;
    cin >> k;
    string l = f(k);
    cout << l;
    return 0;
}

样例全过，但……