#include <iostream>
using namespace std;
typedef long long LL;
int main(int argc, char* argv[])
{
	LL X,Y,Z;
	cin>>X>>Y>>Z;
	if (X<=Z && Z>0){
		Z--;
	}
	if (Y<=Z && Z>0){
		Z--;
	}
	cout<<Z<<endl;
	return 0;
}