#include <iostream>
#include <algorithm>
bool numai_zero(const std::string& s) {
if (!s.size())
return false;
size_t i = 0;
while (i < s.size())
if (s[i++] != '0')
return false;
return true;
}
int main() {
std::string s;
char c;
std::cin >> s >> c;
s.erase(std::remove(s.begin(), s.end(), c), s.end());
std::cout << (numai_zero(s) ? "0" : s.size() ? std::to_string(std::stoi(s)) : "-1");
}