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