import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time,copy,functools

sys.setrecursionlimit(10**7)
inf = 10**20
eps = 1.0 / 10**10
mod = 998244353
dd = [(0,-1),(1,0),(0,1),(-1,0)]
ddn = [(0,-1),(1,-1),(1,0),(1,1),(0,1),(-1,-1),(-1,0),(-1,1)]

def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def S(): return input()
def pf(s): return print(s, flush=True)


def main():
    rr = []

    while True:
        N,M,L,K,A,H = LI()
        if N == 0:
            break
        S = set()
        if L > 0:
            S = set(LI())
        e = collections.defaultdict(list)
        for _ in range(K):
            a,b,d = LI()
            e[a].append((b,d))
            e[b].append((a,d))

        def search(s):
            d = collections.defaultdict(lambda: inf)
            d[(-M,s)] = 0
            q = []
            heapq.heappush(q, (0, -M, s))
            v = collections.defaultdict(bool)
            while len(q):
                k, m, u = heapq.heappop(q)
                if v[(m,u)]:
                    continue
                for mm in range(m,1):
                    v[(mm,u)] = True

                for uv, ud in e[u]:
                    if ud > -m or v[(m+ud,uv)]:
                        continue
                    vd = k + ud
                    vm = m+ud
                    if uv in S:
                        vm = -M
                    if d[(vm,uv)] > vd:
                        for mm in range(vm,1):
                            d[(mm,uv)] = vd
                        heapq.heappush(q, (vd, vm, uv))

            return d

        d = search(A)
        r = inf
        for k in list(d.keys()):
            if k[1] == H and r > d[k]:
                r = d[k]
        if r == inf:
            rr.append('Help!')
        elif r <= M:
            rr.append(r)
        else:
            rr.append(r*2-M)

    return '\n'.join(map(str,rr))


print(main())




### FIXED CODE ###

import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time,copy,functools

sys.setrecursionlimit(10**7)
inf = 10**20
eps = 1.0 / 10**10
mod = 998244353
dd = [(0,-1),(1,0),(0,1),(-1,0)]
ddn = [(0,-1),(1,-1),(1,0),(1,1),(0,1),(-1,-1),(-1,0),(-1,1)]

def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def S(): return input()
def pf(s): return print(s, flush=True)


def main():
    rr = []

    while True:
        N,M,L,K,A,H = LI()
        if N == 0:
            break
        S = set()
        if L > 0:
            S = set(LI())
        else:
            input()
        e = collections.defaultdict(list)
        for _ in range(K):
            a,b,d = LI()
            e[a].append((b,d))
            e[b].append((a,d))

        def search(s):
            d = collections.defaultdict(lambda: inf)
            d[(-M,s)] = 0
            q = []
            heapq.heappush(q, (0, -M, s))
            v = collections.defaultdict(bool)
            while len(q):
                k, m, u = heapq.heappop(q)
                if v[(m,u)]:
                    continue
                for mm in range(m,1):
                    v[(mm,u)] = True

                for uv, ud in e[u]:
                    if ud > -m or v[(m+ud,uv)]:
                        continue
                    vd = k + ud
                    vm = m+ud
                    if uv in S:
                        vm = -M
                    if d[(vm,uv)] > vd:
                        d[(vm,uv)] = vd
                        heapq.heappush(q, (vd, vm, uv))

            return d

        d = search(A)
        r = inf
        for k in list(d.keys()):
            if k[1] == H and r > d[k]:
                r = d[k]
        if r == inf:
            rr.append('Help!')
        elif r <= M:
            rr.append(r)
        else:
            rr.append(r*2-M)

    return '\n'.join(map(str,rr))


print(main())