#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <iomanip>
#include <cmath>
#include <functional>
using namespace std;
#define diff(x,y) ((x > y) ? (x - y) : (y - x))
#define us(x) ((x > 0) ? x : x * -1)
#define change(x) (x ? false : true)
#define lli long long int

int main() {
	int ans;
	int x, y, r;
	cin >> x >> y >> r;
	ans = us(x) + us(y) + sqrt(2) * r + 1;

	cout << ans << endl;
	return 0;
}