#include <bits/stdc++.h>
using namespace std;
int main(){
    int x,y,n,a;
    cin>>x>>y>>n;
	a=n-(x+y) ;
	cout<<a;
}
/**************************************************************
	Problem: 1597
	User: huangluowei
	Language: C++
	Result: Accepted
	Time:13 ms
	Memory:2072 kb
****************************************************************/