#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int M = 10000;

ll cnt(ll X, ll Y, ll R, ll lim) {
    ll a = 0;
    ll b = M;
    ll res = 0;

    auto fn = [&](int t, int i) {
        return (t - X) * (t - X) + (i - Y) * (i - Y) <= R * R;
    };

    for (ll i = (Y + R) - (Y + R) % M; i >= lim; i -= M) {
        while (fn(b, i)) {
            b += M;
        }
        while (fn(a, i)) {
            a -= M;
        }

        res += (b - a - M) / M;
    }
    return res;
}

int main() {
    ld x, y, r;
    cin >> x >> y >> r;

    ll ans = 0;
    ll X = round(x * M);
    ll Y = round(y * M);
    ll R = round(r * M);
    X %= M;
    Y %= M;

    ans += cnt(X, Y, R, M);
    ans += cnt(X, -Y, R, 0);

    cout << ans << endl;

    return 0;
}
#include <bits/stdc++.h>
using int32 = int;
using int64 = long long;
using namespace std;

class Solution
{
#define int int64
#define sfor(i, n) for (int i = 1; i <= n; ++i)
#define tfor(i, n) for (int i = 0; i < n; ++i)

    int x, y, r, res = 0;

    void SHURU()
    {
        double a, b, c;
        cin >> a >> b >> c;
        x = round(a * 10000);
        y = round(b * 10000);
        r = round(c * 10000);
    }

    void SHUCHU()
    {
        cout << res << endl;
    }

    bool inCircle(int dx, int dy)
    {
        return dx * dx + dy * dy <= r * r;
    }

    void CHULI()
    {
        x %= 10000;
        y %= 10000;
        int l = 0, r = 1;
        for (int i = 1000100000; i >= 0; i -= 10000)
        {
            while (inCircle(x - l * 10000, y + i))
                --l;
            while (inCircle(x - r * 10000, y + i))
                ++r;
            res += r - l - 1;
        }
        l = 0;
        r = 1;
        for (int i = 1000100000; i >= 10000; i -= 10000)
        {
            while (inCircle(x - l * 10000, y - i))
                --l;
            while (inCircle(x - r * 10000, y - i))
                ++r;
            res += r - l - 1;
        }
    }

public:
    Solution()
    {
        SHURU();
        CHULI();
        SHUCHU();
    }
#undef int
#undef tfor
#undef sfor
};

int32 main()
{
#ifdef LILY
    while (1)
    {
#endif
        Solution();
#ifdef LILY
    }
#endif
    return 0;
}
