#include <bits/stdc++.h>   using namespace std;   vector<long long> v;   bool super(string s) {     int sv = 0, f = 0;     for (int i = 0; i < s.length(); ++i) {       (s[i] ==  7  ? sv += 1 : f += 1);     }     return (sv == f ? true : false);   }   long long strtoll(string s) {     long long res = 0;     for (int i = 0; i < s.length(); ++i) {       res = res * 10 + (s[i] -  0 );     }     return res;   }   void gennbrs(string s) {     if (s.length() == 11) return;     if (s !=    and super(s)) v.push_back(strtoll(s));     gennbrs(s +  4 );     gennbrs(s +  7 );   }   int main() {     gennbrs(  );     sort(v.begin(), v.end());     int n;     scanf( %d , &n);     for (int i = 0; i < v.size(); ++i) {       if (v[i] >= n) {         cout << v[i] << endl;         break;       }     }     return 0;   }   