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

bool isValidString(string str) {
    for (char c : str) {
        if ( !isalpha(c)&& c !=' ') {
            return false;
        }
    }
    return true;
}
int main() {
    string word1, word2;
    getline(cin, word1);
    getline(cin, word2)'
    
    if(!isValidString(word1) || !isValidString(word2)) {
        cout << "Invalid input" << endl;
        return 0;
    }
    
    string result = " ";
    int i= 0,j = 0;
    int len1=word1.length();
    int len2=word2.length();
    
    while (i < len1 && j < len2) {
        result += word1[i];
        i++;
        result += word2[i];
        j++;
    }
    while (i < len1) {
        result += word2[i];
    }
    
    while ( i< len2) {
        result += word2[j];
        i++;
    }
    cout << result << endl;
    
    return 0;
    
}