#include<bits/stdc++.h> 
using namespace std;
int x,y,n;
float q;
int main(){
    cin>>x>>y>>n;
    q=n-(x+y);  
    cout<<q;
}
/**************************************************************
	Problem: 1597
	User: chenyichuen
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/