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


    return 0;
}

/**************************************************************
	Problem: 1597
	User: linyuhang
	Language: C++
	Result: Compile Error
****************************************************************/