import sys
input = sys.stdin.readline

N,M=list(map(int,input().split()))

mod=998244353

def prod(A,B,k,l,m):# A:k*l,B:l*m
    C=[[None for i in range(m)] for j in range(k)]

    for i in range(k):
        for j in range(m):
            ANS=0
            for pl in range(l):
                ANS=(ANS+A[i][pl]*B[pl][j])%mod

            C[i][j]=ANS

    return C

def plus(A,B,k,l):# a,B:k*l
    C=[[None for i in range(l)] for j in range(k)]

    for i in range(k):
        for j in range(l):
            C[i][j]=(A[i][j]+B[i][j])%mod

    return C

E=[[] for i in range(N)]

for i in range(M):
    x,y=list(map(int,input().split()))
    x-=1
    y-=1
    E[x].append(y)
    E[y].append(x)

S,T,A,B=list(map(int,input().split()))
A-=1
B-=1

X=[[0]*N for i in range(N)]

for i in range(N):
    LEN=len(E[i])
    p=pow(LEN,mod-2,mod)

    for to in E[i]:
        X[i][to]=p

POWA=[X]

for i in range(60):
    POWA.append(prod(POWA[-1],POWA[-1],N,N,N)) # ベキを求めて

n=S-1
X=[[0]*N]
X[0][0]=1

#print(X)
while n:
    X=prod(X,POWA[n.bit_length()-1],1,N,N) # n乗の場合
    n-=1<<(n.bit_length()-1)

#print(X)

bunbo=X[0][A]

n=T-1
X=[[0]*N]
X[0][0]=1

while n:
    X=prod(X,POWA[n.bit_length()-1],1,N,N) # n乗の場合
    n-=1<<(n.bit_length()-1)
    
for i in range(N):
    if i==B:
        continue
    X[0][i]=0

n=S-T
while n:
    X=prod(X,POWA[n.bit_length()-1],1,N,N) # n乗の場合
    n-=1<<(n.bit_length()-1)

#print(X)

bunshi=X[0][A]

ANS=bunshi*pow(bunbo,mod-2,mod)%mod

print(ANS)