#include <stdio.h>#include <string.h>#include <algorithm>using namespace std;int n;double vx,vy,t;struct str{ double x,y; double x1,y1,x2,y2;};str st[10];double ans;int a[10];void dfs(){ int i,j; double temp = 0; double mx1,mx2,my1,my2; mx1 = my1 = 1e100; mx2 = my2 = -1e100; for (i = 0;i < n;i++) { j = a[i]; st[j].x1 = st[j].x - temp * vx; st[j].y1 = st[j].y - temp * vy; st[j].x2 = st[j].x + temp * vx; st[j].y2 = st[j].y + temp * vy; if (st[j].x2 < mx1) mx1 = st[j].x2; if (st[j].y2 < my1) my1 = st[j].y2; if (st[j].x1 > mx2) mx2 = st[j].x1; if (st[j].y1 > my2) my2 = st[j].y1; temp += t; } double t1,t2; t1 = (mx2 - mx1) / (vx * 2); t2 = (my2 - my1) / (vy * 2); mx1 = my1 = 1e100; mx2 = my2 = -1e100; for (i = 1;i < n;i++) { j = a[i]; if (st[j].x2 < mx1) mx1 = st[j].x2; if (st[j].y2 < my1) my1 = st[j].y2; if (st[j].x1 > mx2) mx2 = st[j].x1; if (st[j].y1 > my2) my2 = st[j].y1; temp += t; } if (st[a[0]].x >= mx2 && st[a[0]].x <= mx1) t1 -= min(st[a[0]].x - mx2, mx1 - st[a[0]].x) / vx; if (st[a[0]].y >= my2 && st[a[0]].y <= my1) t2 -= min(st[a[0]].y - my2, my1 - st[a[0]].y) / vy; temp = max(t1,t2); temp += t * (n - 1); if (temp < ans) ans = temp;}int main(){ int i,j,k; while (scanf("%d%lf%lf%lf", &n, &vx, &vy, &t) != EOF) { for (i = 0;i < n;i++) scanf("%lf%lf", &st[i].x, &st[i].y); for (i = 0;i < n;i++) a[i] = i; ans = 1e100; dfs(); while (next_permutation(a,a + n)) { dfs(); } printf("%.8lfn", ans); } return 0;}
