import heapq n,m=map(int,input().split()) G=[[] for i in range(n)] for i in range(m): a,b,c,x=map(int,input().split()) G[a-1].append((b-1,c,x)) G[b-1].append((a-1,c,x)) checked=set() checked_passed=set() d=[float('inf') for i in range(n)] d[-1]=0 d_passed=[float('inf') for i in range(n)] q=[] heapq.heappush(q,[0,n-1,0]) while q and len(checked_passed)