#include<bits/stdc++.h>
using namespace std;

int main(){
	cin.tie(0),ios::sync_with_stdio(false);
	int x,y,r; cin>>x>>y>>r;
	int mx=(sqrtl(x*x+y*y)+r)*(sqrtl(x*x+y*y)+r);
	int ans=1;
	while(ans*ans/2<=mx)++ans;
	cout<<ans<<"\n"s;
}