//div2 hard,indeedNow D
#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9+7;
typedef long long ll;
const int INF = 1e9;

int main(void) {
	int x,y,r;
	cin >> x >> y >> r;
	cout << ceil(abs(x)+abs(y)+sqrt(2.)*r) << endl;
	return 0;
}