mod = 998244353
def main():
    n, m = list(map(int, input().split()))
    node = [[] for _ in range(n)]
    for _ in range(m):
        u, v = list(map(lambda x: int(x)-1, input().split()))
        node[u].append(v)
        node[v].append(u)
    s, t, a, b = list(map(lambda x: int(x)-1, input().split()))
    def cal(t, s):
        dp = [0] * n
        dp[s] = 1
        A = [[0 for x in range(n)] for y in range(n)]
        for u in range(n):
            for v in node[u]:
                A[u][v] = pow(len(node[u]), -1, mod)
        while t:
            if t & 1:
                ndp = [0] * n
                for u in range(n):
                    for v in range(n):
                        ndp[v] = (ndp[v] + dp[u]*A[u][v]) % mod
                dp = ndp
            NA = [[0 for _ in range(n)] for _ in range(n)]
            for u in range(n):
                for w in range(n):
                    for v in range(n):
                        NA[u][v] = (NA[u][v] + A[u][w]*A[w][v]) % mod
            A = NA
            t //= 2
        return dp
    ans1 = cal(s, 0)[a]
    ans0 = cal(t, 0)[b] * cal(s-t, b)[a] % mod
    return ans0 * pow(ans1, -1, mod) % mod
print(main())