#include<bits/stdc++.h>
using namespace std;
int main(){
	int x,y,n;
	cin>>x>>y>>n;
	cout<<n-(x+y);
	
}
/**************************************************************
	Problem: 1597
	User: baizhoudeyueguang
	Language: C++
	Result: Accepted
	Time:25 ms
	Memory:2072 kb
****************************************************************/