Tietoverkko

N = int(input())
 
NPairs = []
Pairs = []
for I in range(N):
	Pair = input().split(" ")
	Pairs.append([int(Pair[0]), int(Pair[1])])
#print("Full network:", Pairs)
 
def GetNumConn():
	NumConn = [0 for I in range(N + 1)]
	for I in range(1, N + 1):
		for Pair in Pairs:
			if Pair[0] == I or Pair[1] == I:
				NumConn[I] += 1
	return NumConn
 
def SingleConn():
	Changed = False
	NumConn = GetNumConn()
	for I in range(1, N + 1):
		if NumConn[I] == 1:
			for Pair in Pairs:
				if Pair[0] == I or Pair[1] == I:
					NPairs.append(Pair)
					Pairs.remove(Pair)
					Changed = True
	return Changed
 
def MultiConn():
	CurrNodes = []
	CurrNodes.append([Pairs[0][0], 0])
	VisNodes = []
	#print("Start node:", CurrNodes[0])
	Changed = False
	while not Changed:
		NewNode = False
		for Node in CurrNodes:
			if not NewNode:
				#print("Node:", Node)
				for Pair in Pairs:
					for I in range(2):
						if Pair[I] == Node[0] and Pair[(I + 1) % 2] != Node[1]:
							if Pair[(I + 1) % 2] in VisNodes or Pair[(I + 1) % 2] in CurrNodes:
								#print("Visited Node:", Pair[(I + 1) % 2])
								Pairs.remove(Pair)
								Changed = True
							else:
								#print("New Node:", Pair[(I + 1) % 2])
								CurrNodes.append([Pair[(I + 1) % 2], Node[0]])
								NewNode = True
				CurrNodes.remove(Node)
				VisNodes.append(Node[0])
	print(Pairs)
	for Pair in Pairs:
		if not Pair in NPairs:
			NPairs.append(Pair)
					
 
while 42:
	if not SingleConn():
		break
 
print(len(NPairs))

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 7

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED