Buggy python submission (verdict: Time Limit Exceeded):
from bisect import bisect_left

n,m = list(map(int,input().split()))
a = [[0] for i in range(n)]
b = [None]*m
for i in range(m):
    p,s = list(map(int,input().split()))
    p-=1
    a[p].append(s)
    b[i] = [p,s]
for i in range(len(a)):
    a[i].sort()
for i in range(len(b)):
    ken = b[i][0]
    si = a[ken].index(b[i][1])
    si = bisect_left(a[ken], b[i][1])
    ken = str(ken+1).zfill(6)
    si = str(si).zfill(6)
    print("".join([ken,si]))

Fixed submission:
from bisect import bisect_left


n,m = list(map(int,input().split()))
a = [[0] for i in range(n)]
b = [None]*m
for i in range(m):
    p,s = list(map(int,input().split()))
    p-=1
    a[p].append(s)
    b[i] = [p,s]
for i in range(len(a)):
    a[i].sort()
for i in range(len(b)):
    ken = b[i][0]
    si = bisect_left(a[ken], b[i][1])
    ken = str(ken+1).zfill(6)
    si = str(si).zfill(6)
    print("".join([ken,si]))

Buggy python submission (verdict: Time Limit Exceeded):
n,m = list(map(int,input().split()))
a = [[0] for i in range(n)]
b = [None]*m
for i in range(m):
    p,s = list(map(int,input().split()))
    p-=1
    a[p].append(s)
    b[i] = [p,s]
for i in range(len(a)):
    a[i].sort()
for i in range(len(b)):
    ken = b[i][0]
    si = a[ken].index(b[i][1])
    ken = str(ken+1).zfill(6)
    si = str(si).zfill(6)
    print("".join([ken,si]))

Fixed submission:
from bisect import bisect_left


n,m = list(map(int,input().split()))
a = [[0] for i in range(n)]
b = [None]*m
for i in range(m):
    p,s = list(map(int,input().split()))
    p-=1
    a[p].append(s)
    b[i] = [p,s]
for i in range(len(a)):
    a[i].sort()
for i in range(len(b)):
    ken = b[i][0]
    si = bisect_left(a[ken], b[i][1])
    ken = str(ken+1).zfill(6)
    si = str(si).zfill(6)
    print("".join([ken,si]))

Buggy python submission (verdict: Runtime Error):
n,m = list(map(int,input().split()))
a = [[None] for i in range(n+1)]
b = [None]*m
for i in range(m):
    p,s = list(map(int,input().split()))
    a[p].append(s)
    b[i] = [p,s]
print(a)
for i in a:
    a[i].sort()
print(a)
for i in b:
    ken = b[i][0]
    si = a[ken].index(b[i][1]) +1
    ken = str(ken).zfill(6)
    si = str(si).zfill(6)
    print("".join([ken,si]))

Fixed submission:
from bisect import bisect_left


n,m = list(map(int,input().split()))
a = [[0] for i in range(n)]
b = [None]*m
for i in range(m):
    p,s = list(map(int,input().split()))
    p-=1
    a[p].append(s)
    b[i] = [p,s]
for i in range(len(a)):
    a[i].sort()
for i in range(len(b)):
    ken = b[i][0]
    si = bisect_left(a[ken], b[i][1])
    ken = str(ken+1).zfill(6)
    si = str(si).zfill(6)
    print("".join([ken,si]))

Buggy python submission (verdict: Time Limit Exceeded):
n,m = list(map(int,input().split()))
a = [[] for i in range(n+1)]
b = []
for i in range(m):
    p,s = list(map(int,input().split()))
    a[p].append(s)
    b.append([p,s])

for i in range(n+1):
    a[i].sort()

for i in range(m):
    ken = b[i][0]
    si = a[ken].index(b[i][1]) +1
    ken = str(ken).zfill(6)
    si = str(si).zfill(6)
    print("".join([ken,si]))

Fixed submission:
from bisect import bisect_left


n,m = list(map(int,input().split()))
a = [[0] for i in range(n)]
b = [None]*m
for i in range(m):
    p,s = list(map(int,input().split()))
    p-=1
    a[p].append(s)
    b[i] = [p,s]
for i in range(len(a)):
    a[i].sort()
for i in range(len(b)):
    ken = b[i][0]
    si = bisect_left(a[ken], b[i][1])
    ken = str(ken+1).zfill(6)
    si = str(si).zfill(6)
    print("".join([ken,si]))