#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>
#include <cmath>

using namespace std;

int main() {
	int x, y, r;

	cin >> x >> y >> r;
	int ans = floor(abs(x) + abs(y) + sqrt(2) * r + 1);
	cout << ans << endl;
	return 0;
}