func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, s;   void dfs(long long x, long long s4, long long s7) {     if (n <= x && (x < s || s == 0) && s4 == s7) s = x;     if (x <= n * 100) {       dfs(x * 10 + 4, s4 + 1, s7);       dfs(x * 10 + 7, s4, s7 + 1);     }   }   int main() {     cin >> n;     dfs(0, 0, 0);     if (n <= 47) s = 47;     cout << s;   }   