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