#include <bits/stdc++.h>
using namespace std;
int main(){
    for(int i=100000;i<1000000;i++){
        if(i/10+700000==4*i&&i%10==7){
            cout<<i;
            return 0;
        }
    }
    return 0;
}
/**************************************************************
	Problem: 1013
	User: wengsihan
	Language: C++
	Result: Accepted
	Time:3 ms
	Memory:2072 kb
****************************************************************/