# Finding Bridges in Undirected Graph
def computeBridges(l):
 id = 0
 n = len(l) # No of vertices in graph
 low = [0] * n
 visited = [False] * n

 def dfs(at, parent, bridges, id):
 visited[at] = True
 low[at] = id
 id += 1
 for to in l[at]:
 if to == parent:
 pass
 elif not visited[to]:
 dfs(to, at, bridges, id)
 low[at] = min(low[at], low[to])
 if at < low[to]:
 bridges.append([at, to])
 else:
 # This edge is a back edge and cannot be a bridge
 low[at] = min(low[at], to)

 bridges = []
 for i in range(n):
 if (not visited[i]):
 dfs(i, -1, bridges, id)
 print(bridges)
 
l = {0:[1,2], 1:[0,2], 2:[0,1,3,5], 3:[2,4], 4:[3], 5:[2,6,8], 6:[5,7], 7:[6,8], 8:[5,7]}
computeBridges(l)