# https://yukicoder.me/problems/no/3635

MOD = 998244353

def prod_matrix(left, right):
    n = len(left)
    new_matrix = [[0] * n for _ in range(n)]
    for i in range(n):
        for j in range(n):
            for k in range(n):
                new_matrix[i][j] += (left[i][k] * right[k][j]) % MOD
                new_matrix[i][j] %= MOD
    return new_matrix

def prod_vector(matrix, vector):
    n = len(vector)
    new_vector = [0] * n
    for i in range(n):
        for j in range(n):
            new_vector[i] += (matrix[i][j] * vector[j]) % MOD
            new_vector[i] %= MOD
    return new_vector

def prob(N, base_matrix, interval_time, start_i, end_i):
    matrix = []
    for row in base_matrix:
        matrix.append(row.copy())

    vector = [0] * N
    vector[start_i] = 1
    while interval_time > 0:
        if interval_time % 2 == 1:
            vector = prod_vector(matrix, vector)

        matrix = prod_matrix(matrix, matrix)
        interval_time //= 2
    return vector[end_i]



def main():
    N, M = map(int, input().split())
    next_nodes = [[] for _ in range(N)]
    for _ in range(M):
        u,v  = map(int, input().split())
        next_nodes[u - 1].append(v - 1)
        next_nodes[v - 1].append(u - 1)
    S, T, A, B = map(int, input().split())
    A -= 1
    B -= 1

    matrix = [[0] * N for _ in range(N)]
    for from_i in range(N):
        n = len(next_nodes[from_i])
        inv_n = pow(n, MOD - 2, MOD)
        for to_i in next_nodes[from_i]:
            matrix[to_i][from_i] = inv_n


    prob_b = prob(N, matrix, T - 1, 0, B)    
    prob_a = prob(N, matrix, S - 1, 0, A) 
    prob_b_to_a = prob(N, matrix, S - T, B, A)

    answer = (prob_b_to_a * prob_b) % MOD
    answer *= pow(prob_a, MOD - 2, MOD)
    answer %= MOD
    print(answer)





    





if __name__ == "__main__":
    main()