#include "iostream"
#include "climits"
#include "list"
#include "queue"
#include "stack"
#include "set"
#include "functional"
#include "algorithm"
#include "string"
#include "map"
#include "unordered_map"
#include "unordered_set"
#include "iomanip"
#include "cmath"
#include "random"
#include "bitset"
#include "cstdio"
#include "numeric"
#include "cassert"
#include "ctime"

using namespace std;

constexpr long long int MOD = 1000000007;
//constexpr int MOD = 1000000007;
//constexpr int MOD = 998244353;
//constexpr long long int MOD = 998244353;
constexpr double EPS = 1e-9;

//int N, M, K, H, W, L, R;
long long int N, M, K, H, W, L, R;


int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> W >> H;
	long long int v, t;
	cin >> v >> t;
	long long int sx, sy, gx, gy;
	cin >> sx >> sy >> gx >> gy;
	int dif = v * t / min(H,W) + 10;
	long long int ans = 0;
	for (int i = -dif; i <= dif; i++) {
		long long int x = sx, y = sy;
		if (i % 2)y = H - y;
		y += i * H;
		if ((y - gy)*(y - gy) + (x - gx)*(x - gx) <= v * v*t*t)ans++;
		L = 0, R = dif;
		while (R - L > 1) {
			int mid = (R + L) / 2;
			x = sx;
			if (mid % 2)x = W - x;
			x += mid * W;
			if ((y - gy)*(y - gy) + (x - gx)*(x - gx) <= v * v*t*t)L = mid;
			else R = mid;
		}
		ans += L;
		L = 0, R =dif;
		while (R - L > 1) {
			int mid = (R + L) / 2;
			x = sx;
			if (mid % 2)x = W - x;
			x -= mid * W;
			if ((y - gy)*(y - gy) + (x - gx)*(x - gx) <= v * v*t*t)L = mid;
			else R = mid;
		}
		ans += L;
	}
	cout << ans << endl;
}
