#include <iostream>
using namespace std;

int main() {
    int x, y, n;
    cin >> x >> y >> n;
    cout << n - x - y << endl;
    return 0;
}    
/**************************************************************
	Problem: 1597
	User: fuyijun
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/