#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,x,y;
	cin>>x>>y>>n;
	cout<<n-(y+x)<<endl;
	return 0;
	
}
/**************************************************************
	Problem: 1597
	User: tangkaixuan
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/