#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>

using namespace std;
typedef long long ll;

int main(void) {
    int x, y, r;
    cin >> x >> y >> r;
    double p = sqrt(x*x+y*y)+r;
    p /= sqrt(2)/2;
    cout << (int)p + 1 << endl;
    return 0;
}