import sys
input = sys.stdin.readline
from heapq import *

def dijkstra():
    dist = [[10**18]*(10**4+10) for _ in range(N)]
    dist[0][T[0]] = T[0]
    pq = [(T[0], T[0])]
    
    while pq:
        d, vt = heappop(pq)
        v, t = divmod(vt, 10**6)
        
        if dist[v][t]<d:
            continue
        
        for nv, w in G[v]:
            if t+T[nv]<10**4+10 and dist[nv][t+T[nv]]>dist[v][t]+w//t+T[nv]:
                dist[nv][t+T[nv]] = dist[v][t]+w//t+T[nv]
                heappush(pq, (dist[nv][t+T[nv]], nv*10**6+t+T[nv]))
    
    return min(dist[-1])-T[-1]

N, M = map(int, input().split())
G = [[] for _ in range(N)]

for _ in range(M):
    A, B, C = map(int, input().split())
    G[A-1].append((B-1, C))
    G[B-1].append((A-1, C))

T = list(map(int, input().split()))
print(dijkstra())