#include <iostream>

using namespace std;

int main() {
    int x, y, z;
    cin >> x >> y >> z;

    int c = 0;
    for (int i = 1; i <= z; i++) {
        if (i == x || i == y) {
            continue;
        }
        c++;
    }
    cout << c << endl;

    return 0;
}