#include <bits/stdc++.h>
int main() {
// NOTE: 1. range of int, 2. check if input is a valid number
int input, output = 0, base = 1;
std::cin >> input;
while (input) {
int mod = input % 10;
if (mod % 2 != 0) {
output += mod * base;
base *= 10;
}
input /= 10;
}
std::cout << output << std::endl;
return 0;
}