#include<bits/stdc++.h> 
using namespace std;
int x,y,n;
float q=0;
int main() 
    cin>>x>>y>>n;
    q=n-(x+y)*0.9;	
    printf(%.f1,q);
}
/**************************************************************
	Problem: 1598
	User: chenyichuen
	Language: C++
	Result: Compile Error
****************************************************************/