#include <iostream>
using namespace std;

int N, M, L, K, A, H, F[120], B[120][120];

int main() {
	while (1) {
		cin >> N >> M >> L >> K >> A >> H;
		if (!(N | M | L | K | A | H)) break;
		memset(F, 0, sizeof(F));
		memset(B, 0, sizeof(B));
		for (int i = 0; i < L; i++) {
			int f; cin >> f; F[f] = 1;
		}
		F[A] = F[H] = 1;
		for (int i = 0; i < K; i++) {
			int x, y, t; cin >> x >> y >> t;
			B[x][y] = B[y][x] = t;
		}
		for (int i = 0; i < N; i++)
		 for (int j = 0; j < N; j++) if (B[j][i])
		  for (int k = 0; k < N; k++) if (B[i][k])
		   if (!B[j][k] || B[j][i] + B[i][k] < B[j][k])
			B[j][k] = B[j][i] + B[i][k];
		for (int i = 0; i < N; i++)
		 for (int j = 0; j < N; j++) {
			if (!F[i] || !F[j] || M < B[i][j])
			 B[i][j] = 0;
		}
		for (int i = 0; i < N; i++)
		 for (int j = 0; j < N; j++) if (B[j][i])
		  for (int k = 0; k < N; k++) if (B[i][k])
		   if (!B[j][k] || B[j][i] + B[i][k] < B[j][k])
			B[j][k] = B[j][i] + B[i][k];
		if (!B[A][H]) printf("Help!\n");
		else printf("%d\n", (M < B[A][H]) ? B[A][H] * 2 - M: B[A][H]);
	}
	return 0;
}