import os import sys import heapq N, M = map(int, input().split(' ')) e={} for i in range(N): for j in range(N): e[(i,j)] = sys.maxsize e={} for i in range(N): e[i] = {} for i in range(M): v1, v2, cost = [int(x) for x in input().split(' ')] e[v1 -1][v2 -1] = cost e[v2 -1][v1 -1] = cost d = [sys.maxsize] * N d_exe = [sys.maxsize] * N d[0] = 0 d_exe[0] = 0 h = [] heapq.heappush(h, (0,0)) while len(h) > 0: p = heapq.heappop(h) if d[p[1]] 0: p = heapq.heappop(h) if d[p[1]]