#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;++i)
using namespace std;

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