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

/**************************************************************
	Problem: 1597
	User: zhengzihao3
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/