#include <bits/stdc++.h>
#define int long long
using namespace std;

signed main() {

  int X, Y, Z;
  cin >> X >> Y >> Z;
  
  int ans = 0;
  for( int i = 1; i <= Z; i++ ){
    if( i == X || i == Y ){
      continue;
    }else{
      ans++;
    }
  }
  cout << ans << endl;
}