#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,y,n;
	cin>>x>>y>>n;
	n=n-x-y;
	cout<<n;
}
/**************************************************************
	Problem: 1597
	User: tonghuawei
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/