#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

int main() {
	int x = ri(), y = ri(), z = ri();
	int cnt = 0;
	for (int i = 1; i <= z; i++) {
		if (i != x && i != y) cnt++;
	}
	std::cout << cnt << std::endl;
	return 0;
}