#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 2000000000



int main(){	
	
	int x,y,r;
	cin>>x>>y>>r;
	
	int ans = 0;
	
	for(int i=-r;i<=r;i++){
		for(int j=-r;j<=r;j++){
	
			if(i*i+j*j>r*r)continue;
			int X = x+i;
			int Y = y+j;
			ans = max(ans,abs(X)+abs(Y)+1);
		}
	}
	cout<<ans<<endl;
	
	return 0;
	
}