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

bool valid(string str)
{
    for(char ch : str)
    {
        if(!isalpha(ch))
        {
            return false;
        }
    }
    return true;
}
int main()
{
    string wordl,word2;
    cin>>word1;
    cin>>word2;
    
    if(!valid(word1) || valid(word2))
    {
        cout<<"Invalid input ";
        return 0;
    
    string result ="";
    int i=0;
    }
    
    
    while(i<word1.length() && i<word2.length())
    {
        result += word1[i];
        result += word2[i];
        i++;
    }
    while(i<word2.length())
    {
        result +=word2[i];
        i++;
    }
    cout<<result;
    return 0;
}