#include <bits/stdc++.h>
using namespace std;
int main(){
	int a,b,n; 
	cin>> a >> b >> n ;
    cout<<n-(a+b); 
	return 0;	
}
/**************************************************************
	Problem: 1597
	User: chenjiahui
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/