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

	return 0;
}
/**************************************************************
	Problem: 1597
	User: linyuhang
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/