import java.util.*;

public class Main {
    static final int MAX = 100 * 1000 + 1;
    static final int MOD = 1000000007;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        long[] volts = new long[MAX];
        volts[0] = 1;
        for (int i = 0; i < n; i++) {
            int x = sc.nextInt();
            for (int j = 1000 * i; j >= 0; j--) {
                volts[j + x] += volts[j];
                volts[j + x] %= MOD;
            }
        }
        long[] sums = new long[MAX];
        for (int i = 1; i < MAX; i++) {
            sums[i] += sums[i - 1] + volts[i];
            sums[i] %= MOD;
        }
        long[] resists = new long[MAX];
        resists[0] = 1;
        for (int i = 0; i < n; i++) {
            int x = sc.nextInt();
            for (int j = 1000 * i; j >= 0; j--) {
                resists[j + x] += resists[j];
                resists[j + x] %= MOD;
            }
        }
        int a = sc.nextInt();
        int b = sc.nextInt();
        long ans = 0;
        for (int i = 1; i * a < MAX; i++) {
            ans += (sums[Math.min(MAX - 1, i * b)] - sums[i * a - 1] + MOD) % MOD * resists[i] % MOD;
            ans %= MOD;
        }
        System.out.println(ans);
    }
}