#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    ll a, b, c; cin >> a >> b >> c;

    if ((a+b) % 2 == 0) cout << c;
    else if ((b+c) % 2 == 0) cout << a;
    else cout << b;

}