using System;

​

​

public class Solution

{

    public static int solution(int A, int B) 

    {

    if (A < 0 || A > 100000000) return -1;

    if (B < 0 || B > 100000000) return -1;

​

    string cadA = A.ToString();

    string cadB= B.ToString();

    string cadC = "";

    for (int i = 0; i < cadA.Length || i < cadB.Length; i++) {

​

        if (i<cadA.Length) cadC= cadC +cadA[i];

        if (i<cadB.Length) cadC= cadC +cadB[i];

    }

​

    return int.Parse(cadC);

    }

    public static void Main()

    {

        Console.WriteLine("Resultado "+solution(12345,678));

    }

}