#include<iostream>
#include<string>
#include<cctype>
using namesapce std;
bool isvalid(string s){
    for(char c : s){
        if(!isalpha(c)){
            return false;
        }
    }
    return true;
}
int main(){
    string w1,w2;
    cin>>w1>>w2;
     if(!isalpha(w1) || !isalpha(w2)){
         cout<<"Invalid input";
         return 0;
     }
     string result = " ";
     int i = 0;
     while(i<w1.length() || i<w2.length()){
         if(i<w1.length())
         result += w1[i];
           if(i<w2.length())
         result += w2[i];
         i++;
     }
     cout<<result;
     return 0;
}