#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    int a, b, c;
    cin >> a >> b >> c;
    if (a == b && b == c) cout << a << endl;
    else if (a != b && b != c && c != a) cout << 6-a-b-c << endl;
    else cout << (a ^ (b ^ c)) << endl;

    return 0;
}