#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define ll long long
#define ld long double
#define ull unsigned long long
#define lcm(a,b) ((a*b)/__gcd(a,b))
#define debug(x) cout << "Debug : " << x << endl;
const double PI = 2 * acos(0.0);
const int MOD = 1000000007;

void solve(){
    ll a, b, c;
    cin >> a >> b >> c;

    if (a % 2 == b % 2){
        cout << c << endl;
    }
    else if (a % 2 == c % 2){
        cout << b << endl;
    }
    else{
        cout << a << endl;
    }
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    solve();
}