#include<bits/stdc++.h>
using namespace std;
int main() {
	int x,y,n,s;
	cin>>x>>y>>n;
	 s=n-(x+y);
	 cout<<s;
    return 0;
}

/**************************************************************
	Problem: 1597
	User: huangcanwu
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/