#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;
using ll=long long;
int main(){
    int x,y,z;
    cin>>x>>y>>z;
    int ans=0;
    while(z!=0){
        if(z!=x&&z!=y)ans++;
        z--;
    }
    cout<<ans<<endl;
}