#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b,c,s;
	cin>>a>>b>>c;
	s=c-a-b;
	printf("%d",s);
}
/**************************************************************
	Problem: 1597
	User: toughuatao1
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/