Buggy python submission (verdict: Time Limit Exceeded):
import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
G = [[] for _ in range(N)]
ans = {}
queue = deque([])
e = []
for l in range(N-1):
    temp = list(map(int,input().split()))
    temp[0] -= 1
    temp[1] -= 1
    e.append(tuple(temp))
    ans[(temp[0],temp[1])] = 0
    ans[(temp[1],temp[0])] = 0
    G[temp[0]].append(temp[1])
    G[temp[1]].append(temp[0])
    if l == 0:
        queue.append(temp[0])
#使えない色
nuc = [[0] for _ in range(N)]
#使った色
auc = []
#答え
def bfs(x):
    k = 1
    for i in G[x]:
        if ans[(x,i)] ==0:
            queue.append(i)
            flag = 1
            while flag:
                if k not in nuc[x]:         
                    ans[(x,i)] = k
                    ans[(i,x)] = k
                    nuc[x].append(k)
                    nuc[i].append(k)
                    if k not in auc:
                        auc.append(k)
                    flag = 0
                else:
                    k += 1
                
while len(queue) > 0:
    next_ = queue.popleft()
    bfs(next_)
print(len(auc))
for m in e:
    print(ans[m])


Fixed submission:
import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
G = [[] for _ in range(N)]
ans = {}
queue = deque([])
e = []
for l in range(N-1):
    temp = list(map(int,input().split()))
    temp[0] -= 1
    temp[1] -= 1
    e.append(tuple(temp))
    ans[(temp[0],temp[1])] = 0
    ans[(temp[1],temp[0])] = 0
    G[temp[0]].append(temp[1])
    G[temp[1]].append(temp[0])
    if l == 0:
        queue.append(temp[0])
#使えない色
nuc = [[0] for _ in range(N)]
#使った色
auc = []
#答え
def bfs(x):
    k = 1
    for i in G[x]:
        if ans[(x,i)] ==0:
            queue.append(i)
            flag = 1
            while flag:
                if k not in nuc[x]:         
                    ans[(x,i)] = k
                    ans[(i,x)] = k
                    nuc[x].append(k)
                    nuc[i].append(k)
                    if k not in auc:
                        auc.append(k)
                    flag = 0
                else:
                    k += 1
                
while len(queue) > 0:
    next_ = queue.popleft()
    bfs(next_)
print(len(auc))
for m in e:
    print(ans[m])

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
G = [[] for _ in range(N)]
e = []
queue = deque([])
for l in range(N-1):
    temp = list(map(int,input().split()))
    temp[0] -= 1
    temp[1] -= 1
    e.append(temp)
    G[temp[0]].append(temp[1])
    G[temp[1]].append(temp[0])
    if l == 0:
        queue.append(temp[0])
#使えない色
nuc = [[0] for _ in range(N)]
#使った色
auc = []
#答え
ans = [[0] * N for _ in range(N)]
def bfs(x):
    k = 1
    for i in G[x]:
        if ans[x][i] ==0:
            queue.append(i)
            flag = 1
            while flag:
                if k not in nuc[x]:         
                    ans[x][i] = k
                    ans[i][x] = k
                    nuc[x].append(k)
                    nuc[i].append(k)
                    if k not in auc:
                        auc.append(k)
                    flag = 0
                else:
                    k += 1
                
while len(queue) > 0:
    next_ = queue.popleft()
    bfs(next_)
print(len(auc))
for m in e:
    print(ans[m[0]][m[1]])

Fixed submission:
import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
G = [[] for _ in range(N)]
ans = {}
queue = deque([])
e = []
for l in range(N-1):
    temp = list(map(int,input().split()))
    temp[0] -= 1
    temp[1] -= 1
    e.append(tuple(temp))
    ans[(temp[0],temp[1])] = 0
    ans[(temp[1],temp[0])] = 0
    G[temp[0]].append(temp[1])
    G[temp[1]].append(temp[0])
    if l == 0:
        queue.append(temp[0])
#使えない色
nuc = [[0] for _ in range(N)]
#使った色
auc = []
#答え
def bfs(x):
    k = 1
    for i in G[x]:
        if ans[(x,i)] ==0:
            queue.append(i)
            flag = 1
            while flag:
                if k not in nuc[x]:         
                    ans[(x,i)] = k
                    ans[(i,x)] = k
                    nuc[x].append(k)
                    nuc[i].append(k)
                    if k not in auc:
                        auc.append(k)
                    flag = 0
                else:
                    k += 1
                
while len(queue) > 0:
    next_ = queue.popleft()
    bfs(next_)
print(len(auc))
for m in e:
    print(ans[m])

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
G = [[] for _ in range(N)]
e = []
queue = deque([])
for l in range(N-1):
    temp = list(map(int,input().split()))
    temp[0] -= 1
    temp[1] -= 1
    e.append(temp)
    G[temp[0]].append(temp[1])
    G[temp[1]].append(temp[0])
    if l == 0:
        queue.append(temp[0])
#使えない色
nuc = [[0] for _ in range(N)]
#使った色
auc = []
#答え
ans = [[0] * N for _ in range(N)]
def bfs(x):
    for i in G[x]:
        if ans[x][i] ==0 and ans[i][x] == 0:
            queue.append(i)
            for k in range(1,N):
                if k not in nuc[x] and k not in nuc[i]:
                    ans[x][i] = k
                    ans[i][x] = k
                    nuc[x].append(k)
                    nuc[i].append(k)
                    if k not in auc:
                        auc.append(k)
                    break
while len(queue) > 0:
    next_ = queue.popleft()
    bfs(next_)
print(len(auc))
for m in e:
    print(ans[m[0]][m[1]])


Fixed submission:
import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
G = [[] for _ in range(N)]
ans = {}
queue = deque([])
e = []
for l in range(N-1):
    temp = list(map(int,input().split()))
    temp[0] -= 1
    temp[1] -= 1
    e.append(tuple(temp))
    ans[(temp[0],temp[1])] = 0
    ans[(temp[1],temp[0])] = 0
    G[temp[0]].append(temp[1])
    G[temp[1]].append(temp[0])
    if l == 0:
        queue.append(temp[0])
#使えない色
nuc = [[0] for _ in range(N)]
#使った色
auc = []
#答え
def bfs(x):
    k = 1
    for i in G[x]:
        if ans[(x,i)] ==0:
            queue.append(i)
            flag = 1
            while flag:
                if k not in nuc[x]:         
                    ans[(x,i)] = k
                    ans[(i,x)] = k
                    nuc[x].append(k)
                    nuc[i].append(k)
                    if k not in auc:
                        auc.append(k)
                    flag = 0
                else:
                    k += 1
                
while len(queue) > 0:
    next_ = queue.popleft()
    bfs(next_)
print(len(auc))
for m in e:
    print(ans[m])

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
G = [[] for _ in range(N)]
e = []
queue = deque([])
for l in range(N-1):
    temp = list(map(int,input().split()))
    temp[0] -= 1
    temp[1] -= 1
    e.append(temp)
    G[temp[0]].append(temp[1])
    G[temp[1]].append(temp[0])
    if l == 0:
        queue.append(temp[0])
#使えない色
nuc = [[0] for _ in range(N)]
#使った色
auc = []
#答え
ans = [[0] * N for _ in range(N)]
def bfs(x):
    for i in G[x]:
        if ans[x][i] ==0 and ans[i][x] == 0:
            queue.append(i)
            for k in range(N):
                if k not in nuc[x] and k not in nuc[i]:
                    ans[x][i] = k
                    ans[i][x] = k
                    nuc[x].append(k)
                    nuc[i].append(k)
                    if k not in auc:
                        auc.append(k)
                    break
while len(queue) > 0:
    next_ = queue.popleft()
    bfs(next_)
print(len(auc))
for m in e:
    print(ans[m[0]][m[1]])

Fixed submission:
import sys
from collections import deque
input = sys.stdin.readline
N = int(input())
G = [[] for _ in range(N)]
ans = {}
queue = deque([])
e = []
for l in range(N-1):
    temp = list(map(int,input().split()))
    temp[0] -= 1
    temp[1] -= 1
    e.append(tuple(temp))
    ans[(temp[0],temp[1])] = 0
    ans[(temp[1],temp[0])] = 0
    G[temp[0]].append(temp[1])
    G[temp[1]].append(temp[0])
    if l == 0:
        queue.append(temp[0])
#使えない色
nuc = [[0] for _ in range(N)]
#使った色
auc = []
#答え
def bfs(x):
    k = 1
    for i in G[x]:
        if ans[(x,i)] ==0:
            queue.append(i)
            flag = 1
            while flag:
                if k not in nuc[x]:         
                    ans[(x,i)] = k
                    ans[(i,x)] = k
                    nuc[x].append(k)
                    nuc[i].append(k)
                    if k not in auc:
                        auc.append(k)
                    flag = 0
                else:
                    k += 1
                
while len(queue) > 0:
    next_ = queue.popleft()
    bfs(next_)
print(len(auc))
for m in e:
    print(ans[m])