#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>

#define ALL(x) (x).begin(),(x).end()
#define REP(i,n) for(int i = 0;i < (n);i++)
#define PI 3.14159265359
#define MOD 1000000007

using namespace std;

int main(){
    int x,y,r,ans;
    cin >> x >> y >> r;
    x *= x < 0 ? -1 : 1;
    y *= y < 0 ? -1 : 1;
    ans = ceil(x+y+2*r/sqrt(2));
    cout << ans << endl;;
    return 0;
}