#include <string> #include <iostream> #include <algorithm> using namespace std; string get_next(string& str) { int len = str.length(); if (len == 0)return string(""); bool num4 = false; for (int i = len - 1; i >= 0; i--) { if (str[i] == '4') {  str[i] = '7';  num4 = true;  break;  } } if (!num4) { return string(len + 1, '4'); } return str; } string Helper(int n) { if (n <= 0)return ""; string result=string("4"); if (n == 1)return result; while (--n) { result = get_next(result); } return result; } int main() { int n; while (cin >> n) { cout << Helper(n) << endl; } return 0; }