#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
typedef long long ll;
using namespace std;

int main() {
    cin.tie(0)->sync_with_stdio(0);

    vector<int> A(3);
    rep(i, 3) cin >> A[i];
    sort(A.begin(), A.end());

    if (A[0] == A[2])
        cout << A[0];
    else if (A[0] == A[1])
        cout << A[2];
    else if (A[1] == A[2])
        cout << A[0];
    else
        cout << 6 - A[0] - A[1] - A[2];
    cout << "\n";

    return 0;
}