#include <iostream>
#include <string>
using namespace std;
int main(){
    string s1;
    cin>>s1;
    string s2;
    cin>>s2;
    for(int i=0;i<s1.length();i++){
        if(!isalpha(s1[i])){
            cout<<"Invalid input";
        }
    }
    for(int z=0;z<s2.length();z++){
        if(!isalpha(s2[i])){
            cout<<"Invalid input";
        }
    }
    for(int k=0;k<s1.length();k++){
        for(int w=0;w<s2.length();w++){
            cout<<s1[k]<<s2[w];
        }
    }
    return 0;
}