#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,y,n,b;
	cin>>x>>y>>n;
	b=n-x-y;
	cout<<b;
}
/**************************************************************
	Problem: 1597
	User: zengyixuan
	Language: C++
	Result: Accepted
	Time:18 ms
	Memory:2072 kb
****************************************************************/