#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,y,x;
	cin>>x>>y>>n;
	cout<<n-y-x;
}



/**************************************************************
	Problem: 1597
	User: zhuangsongyu
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/