input_array = input().split()
num_conns = int(input_array[1])

fwd_conns = {}
back_conns = {}
for i in range(num_conns):
	conn_input = input().split()
	
	try:
		fwd_conns[conn_input[0]].append(conn_input[1])
	except:
		fwd_conns[conn_input[0]] = [conn_input[1]]
		
	try:
		back_conns[conn_input[1]].append(conn_input[0])
	except:
		back_conns[conn_input[1]] = [conn_input[0]]

keys_to_remove = []
for key in fwd_conns.keys():
	if len(fwd_conns[key]) <= 1:
		keys_to_remove.append(key)
for i in keys_to_remove:
	fwd_conns.pop(i)

keys_to_remove = []
for key in back_conns.keys():
	if len(back_conns[key]) <= 1:
		keys_to_remove.append(key)
for i in keys_to_remove:
	back_conns.pop(i)

number = 0
for i in back_conns.keys():
	for j in fwd_conns.keys():
		if i in fwd_conns[j]:
			number += 1

print(number)