C++ :

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;

#define MAXN 100
#define inf 1000000000
#define _clr(x) memset(x,0xff,sizeof(int)*MAXN)

double g[MAXN][MAXN];
int match1[MAXN], match2[MAXN];

int hungary(int m, int n, int mat[][MAXN], int *match1, int *match2) {
	int s[MAXN], t[MAXN], p, q, ret = 0, i, j, k;
	for (_clr(match1),_clr(match2), i = 0; i < m; ret += (match1[i++] >= 0))
		for (_clr(t),s[p = q = 0] = i; p <= q && match1[i] < 0; p++)
			for (k = s[p], j = 0; j < n && match1[i] < 0; j++)
				if (mat[k][j] && t[j] < 0) {
					s[++q] = match2[j];
					t[j] = k;
					if (s[q] < 0)
						for (p = j; p >= 0; j = p) {
							match2[j] = k = t[j];
							p = match1[k];
							match1[k] = j;
						}
				}
	return ret;
}

int main() {
	int n, m, i, j, k, left, right, mid, map[MAXN][MAXN];
	double px[MAXN], py[MAXN], tx[MAXN], ty[MAXN], v, time[MAXN*MAXN], T;
	while (scanf("%d%d", &n, &m) != EOF) {
		for (i = 0; i < n; i++)
			scanf("%lf%lf", &px[i], &py[i]);
		for (i = 0; i < m; i++)
			scanf("%lf%lf", &tx[i], &ty[i]);
		scanf("%lf", &v);
		for (k = i = 0; i < n; i++)
			for (j = 0; j < m; j++) {
				g[i][j] = sqrt((px[i] - tx[j]) * (px[i] - tx[j]) + (py[i]
						- ty[j]) * (py[i] - ty[j])) / v;
				time[k++] = g[i][j];
			}
		sort(time, time + k);
		left = 0;
		right = k;
		while (left < right) {
			mid = (left + right) >> 1;
			memset(map, 0, sizeof(map));
			for (i = 0; i < n; i++)
				for (j = 0; j < m; j++)
					if (g[i][j] <= time[mid])
						map[i][j] = 1;
			if (hungary(n, m, map, match1, match2) == n) {
				T = time[mid];
				right = mid;
			} else
				left = mid + 1;
		}
		printf("%.2lf\n", T);
	}
	return 0;
}