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

bool valid(string str){
    for(char ch : str){
        if(!isalpha(ch)){
            return false;
        }
    }
    return true;
    
}
int main(){
    string word1, word2;
    cin>>world1;
    cin>>world2;
    
    if(!valid(word2) || !valid(word2)){
        cout<<"Invalid input";
        return 0;
    }
    string result ="";
    int i =0;
    
    while(i < word.length() && i< world2.length()){
        result +=word1[1];
        result +=world[2];
        i++;
    }
    while(i<word1.length()){
        result += word1[1];
        i++;
    }
    while(i<word2.length()){
        result += world[2];
        i++;
    }
    cout>>result;
    return 0;
        
    
}