#include <bits/stdc++.h>
#define ll long long
using namespace std;
int main() {
string contaner;
string str;
cin >> str;
cin >> contaner;
int n = str.find('|');
string str1 = str.substr(0, n);
string str2 = str.substr(n + 1);
// cout << str1.size() <<" "<< str2.size() << endl;
if (str1.size() == str2.size()+contaner.size()) {
cout << str1 + '|' << str2 + contaner << endl;
} else if (str1.size()+contaner.size() == str2.size()) {
cout << str1 + contaner + '|' << str2 << endl;
} else
cout << "Impossible" << endl;
return 0;
}
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