# include<bits/stdc++.h>
using namespace std;
int main(){
	int x,y,n,a;
	cin>>x>>y>>n;
	a=n-x-y;
	cout<<a; 
	return 0;
}

/**************************************************************
	Problem: 1597
	User: caiqiaoxi
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/