Buggy python submission (verdict: Runtime Error):
iro = []
iro_i = []
res = []
r = 0
cm = []
for i in range(N+1):
  cm.append([])
N = int(input())
for i in range(N-1):
  a,b = input().split(" ")
  a = int(a)
  b = int(b)
  for cr in set(iro_i) - set(cm[a] + cm[b]):
    res.append(cr+1)
    cm[a].append(cr)
    cm[b].append(cr)
    break
  else:
    iro_i.append(r)
    cm[a].append(r)
    cm[b].append(r)
    res.append(r+1)
    r+=1
print(r+1)
for i in res:
  print(i)




Fixed submission:
import sys
from collections import deque
read = sys.stdin.read

N, *ab = map(int, read().split())

graph = [[] for _ in range(N + 1)]
 
for a, b in zip(*[iter(ab)] * 2):
    graph[a].append(b)
 
color = [0] * (N + 1)
queue = deque([1])
 
while queue:
    V = queue.popleft()
    number = 1
    for v in graph[V]:
        if number == color[V]:
            number += 1
        color[v] = number
        queue.append(v)
        number += 1
 
print(max(color))
for a, b in zip(*[iter(ab)] * 2):
    print(color[b])

Buggy python submission (verdict: Runtime Error):
iro = []
res = []
r = 0
cm = []
for i in range(N):
  cm.append([])
N = int(input())
for i in range(N-1):
  a,b = input().split(" ")
  a = int(a)
  b = int(b)
  cr = 0
  while cr < r
    if a not in iro[cr] and b not in iro[cr]:
      iro[cr].append(a)
      iro[cr].append(b)
      res.append(cr+1)
      break
    cr += 1
  else:
    r = cr
    iro.append([a,b])
    res.append(cr+1)
print(r+1)
for i in res:
  print(i)




Fixed submission:
import sys
from collections import deque
read = sys.stdin.read

N, *ab = map(int, read().split())

graph = [[] for _ in range(N + 1)]
 
for a, b in zip(*[iter(ab)] * 2):
    graph[a].append(b)
 
color = [0] * (N + 1)
queue = deque([1])
 
while queue:
    V = queue.popleft()
    number = 1
    for v in graph[V]:
        if number == color[V]:
            number += 1
        color[v] = number
        queue.append(v)
        number += 1
 
print(max(color))
for a, b in zip(*[iter(ab)] * 2):
    print(color[b])

Buggy python submission (verdict: Time Limit Exceeded):
iro = []
res = []
r = 0
cc = {}
N = int(input())
for i in range(N-1):
  a,b = input().split(" ")
  a = int(a)
  b = int(b)
  cr = 0
  for p in iro:
    if a in iro:
      cr += 1
      continue
    elif b in iro:
      cr += 1
      continue
    elif a not in p and b not in p:
      iro[cr].append(a)
      iro[cr].append(b)
      res.append(cr+1)
      break
    cr += 1
  else:
    r = cr
    iro.append([a,b])
    res.append(cr+1)
print(r+1)
for i in res:
  print(i)




Fixed submission:
import sys
from collections import deque
read = sys.stdin.read

N, *ab = map(int, read().split())

graph = [[] for _ in range(N + 1)]
 
for a, b in zip(*[iter(ab)] * 2):
    graph[a].append(b)
 
color = [0] * (N + 1)
queue = deque([1])
 
while queue:
    V = queue.popleft()
    number = 1
    for v in graph[V]:
        if number == color[V]:
            number += 1
        color[v] = number
        queue.append(v)
        number += 1
 
print(max(color))
for a, b in zip(*[iter(ab)] * 2):
    print(color[b])

Buggy python submission (verdict: Runtime Error):
iro = []
res = []
r = 0
cc = {}
N = int(input())
for i in range(N-1):
  a,b = input().split(" ")
  a = int(a)
  b = int(b)
  cr = 0
  for p in iro:
    if a in iro:
      cr += 1
      continue
    elif b in iro:
      cr += 1
      continue
    elif a not in p and b not in p:
      iro[cr].append(a)
      iro[cr].append(b)
      res.append(cr+1)
      else:
        if cc[a] > 

      break
    cr += 1
  else:
    r = cr
    iro.append([a,b])
    res.append(cr+1)
print(r+1)
for i in res:
  print(i)




Fixed submission:
import sys
from collections import deque
read = sys.stdin.read

N, *ab = map(int, read().split())

graph = [[] for _ in range(N + 1)]
 
for a, b in zip(*[iter(ab)] * 2):
    graph[a].append(b)
 
color = [0] * (N + 1)
queue = deque([1])
 
while queue:
    V = queue.popleft()
    number = 1
    for v in graph[V]:
        if number == color[V]:
            number += 1
        color[v] = number
        queue.append(v)
        number += 1
 
print(max(color))
for a, b in zip(*[iter(ab)] * 2):
    print(color[b])

Buggy python submission (verdict: Runtime Error):
iro = []
res = []
r = 0
cc = {}
N = int(input())
for i in range(N-1):
  a,b = input().split(" ")
  a = int(a)
  b = int(b)
  cr = 0
  for p in iro:
    if a in iro:
      continue
    elif b in iro:
      continue
    elif a not in p and b not in p:
      iro[cr].append(a)
      iro[cr].append(b)
      res.append(cr+1)
      else:
        if cc[a] > 

      break
    cr += 1
  else:
    r = cr
    iro.append([a,b])
    res.append(cr+1)
print(r+1)
for i in res:
  print(i)




Fixed submission:
import sys
from collections import deque
read = sys.stdin.read

N, *ab = map(int, read().split())

graph = [[] for _ in range(N + 1)]
 
for a, b in zip(*[iter(ab)] * 2):
    graph[a].append(b)
 
color = [0] * (N + 1)
queue = deque([1])
 
while queue:
    V = queue.popleft()
    number = 1
    for v in graph[V]:
        if number == color[V]:
            number += 1
        color[v] = number
        queue.append(v)
        number += 1
 
print(max(color))
for a, b in zip(*[iter(ab)] * 2):
    print(color[b])

Buggy python submission (verdict: Time Limit Exceeded):
iro = []
res = []
r = 0

N = int(input())
for i in range(N-1):
  a,b = input().split(" ")
  a = int(a)
  b = int(b)
  cr = 0
  for p in iro:
    if a not in p and b not in p:
      iro[cr].append(a)
      iro[cr].append(b)
      res.append(cr+1)
      break
    cr += 1
  else:
    r = cr
    iro.append([a,b])
    res.append(cr+1)
print(r+1)
for i in res:
  print(i)


Fixed submission:
import sys
from collections import deque
read = sys.stdin.read

N, *ab = map(int, read().split())

graph = [[] for _ in range(N + 1)]
 
for a, b in zip(*[iter(ab)] * 2):
    graph[a].append(b)
 
color = [0] * (N + 1)
queue = deque([1])
 
while queue:
    V = queue.popleft()
    number = 1
    for v in graph[V]:
        if number == color[V]:
            number += 1
        color[v] = number
        queue.append(v)
        number += 1
 
print(max(color))
for a, b in zip(*[iter(ab)] * 2):
    print(color[b])