#include <iostream>
#include <sstream>
#include <math.h>
#include <stack>
#include <set>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <map>
#include <cstdio>
#include <vector>
using namespace std;

#define INF (1 << 30)
#define INFLL (1LL << 60)

int main() {
	int x,y,r;
	cin >> x >> y >> r;
	double ans = sqrt(double(r*r/2.0)) * 2;
	ans += abs(x) + abs(y);
	ans = ans + 0.99999999;
	cout << int(ans) << endl;
	return 0;
}