#include <bits/stdc++.h>
#define PI 3.14159265359
using namespace std;
const int64_t MOD = 1e9 + 7;

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

	x = abs(x);
	y = abs(y);

	int ans = ceil(x + y + sqrt(2) * r);

	cout << ans << endl;
}