View Code of Problem 3831

#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
using namespace std;

int fun(int num)
{
    int sum = 0;
    while (num)
    {
        sum += num % 10;
        num /= 10;
    }
    return sum;
}

int main(void)
{
    long long a, b, c, d;
    while (cin >> a >> b >> c >> d)
    {
        int flag = 1;
        for (int i = 1; i <= 81; i++)
        {
            int x = (i + a) * (i + b) * (i + c) * (i + d);
            if (i == fun(x))
            {
                flag = 0;
                cout << x << endl;
                break;
            }
        }
        if (flag)
            cout << -1 << endl;
    }
}