#include<bits/stdc++.h>
using namespace std;
int main(){
    int x,y,n;
    cin>>x>>y>>n;
    float p;
    cout<<n-(x+y)*0.9;
    return 0;
} 
/**************************************************************
	Problem: 1598
	User: binzicheng1
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/