//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int main(){
  vector<int> X(3);
  cin >> X[0] >> X[1] >> X[2];

  sort(X.begin(), X.end());
  if(X[0] == X[2]){
    printl(X[0]);
  }else if(X[0] == X[1] or X[1] == X[2]){
    X[1] == X[2] ? printl(X[0]) : printl(X[2]);
  }else{
    int ans = 6;

    for(auto x: X) ans -= x;

    printl(ans);
  }

  return 0;
}