#include <cstdio>
#include <iostream>
#include <cmath>
#include <algorithm>

#define eps (1e-6)

using namespace std;

typedef long long LL;

struct vect {
    LL x, y;

    vect() {}

    vect(LL a, LL b) {
        x = a, y = b;
    }

    void read() {
        cin >> x >> y;
    }
};

vect operator - (vect a, vect b) {
    return vect(a.x - b.x, a.y - b.y);
}

LL operator * (vect a, vect b) {
    return a.x * b.x + a.y * b.y;
}

LL rad, q, n, A, B, C;
vect pos, vel;

bool check(LL x, LL y) {
    if ((vect(x, y) - pos) * vel >= 0) {
        if (abs(A * x + B * y + C) / sqrt(double(A * A + B * B)) * 1000 - rad - q > eps)
            return false;
        return true;
    }
    return false;
}

LL count_segment(LL x1, LL x2, LL y) {
    if (abs(x1) % 2 != y % 2)
        x1++;
    if (abs(x2) % 2 != y % 2)
        x2--;

    if (x2 >= x1)
        return (x2 - x1) / 2 + 1;
    return 0;
}

int main() {
    freopen("spacepin.in", "r", stdin);
    freopen("spacepin.out", "w", stdout);

    cin >> rad >> n >> q;
    pos.read();
    vel.read();

    A = vel.y, B = - vel.x;
    C = - A * pos.x - B * pos.y;

    LL res = 0;
    for (LL y = 0; y < n; y++) {
        double x_mid = - double(B * y + C) / A;
        LL x1 = LL(x_mid);

        LL l = - y - 1, r = min(x1 + 1, y + 1);
        LL mem_x1 = r - 1;

        while (l + 1 < r) {
            LL mid = (l + r) / 2;
            if (check(mid, y))
                r = mid;
            else
                l = mid;
        }
        res += count_segment(r, mem_x1, y);

        l = max(x1, - y - 1), r = y + 1;
        LL mem_l = l + 1;
        while (l + 1 < r) {
            LL mid = (l + r) / 2;
            if (check(mid, y))
                l = mid;
            else
                r = mid;
        }
        res += count_segment(mem_l, l, y);
    }

    cout << res << endl;

    return 0;
}