#include <bits/stdc++.h>

using namespace std;
void fast_io() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
}
int main() {
    fast_io();
    int a[3];
    cin >> a[0] >> a[1] >> a[2];
    sort(a, a + 3);
    if (a[0] == a[2]) {
        cout << a[0] << endl;
    } else if (a[0] == a[1]) {
        cout << a[2] << endl;
    } else if (a[1] == a[2]) {
        cout << a[0] << endl;
    } else {
        cout << 6 - a[0] - a[1] - a[2] << endl;
    }
}