#include "bits/stdc++.h"

using namespace std;
typedef long long ll;
#define rep(i, j, n) for (int i = j; i < n; i++)
#define out(ans) cout << ans << endl;
const long long mod = 1e9 + 7;

int main() {

  ll x,y,z;cin>>x>>y>>z;
  ll sum=0;
  for(ll i=1;i<=z;i++){
    if(i==x||i==y)continue;
    sum++;
  }
  out(sum);


  return 0;
}