#include<bits/stdc++.h>
using namespace std;
int x,y,n,z;
int main(){
    cin>>x>>y>>n;
    z=n-(x+y);
    cout<<z<<endl;
}
/**************************************************************
	Problem: 1597
	User: xuezihong1
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/