Buggy python submission (verdict: Runtime Error):
# coding=utf-8
from math import floor, ceil, sqrt, factorial, log, gcd
from itertools import accumulate, permutations, combinations, product, combinations_with_replacement
from bisect import bisect_left, bisect_right
from collections import Counter, defaultdict
from heapq import heappop, heappush, heappushpop, heapify
import copy
import numpy as np
import sys
INF = float('inf')
mod = 10**9+7
sys.setrecursionlimit(10 ** 6)


def lcm(a, b): return a * b / gcd(a, b)

# 1 2 3
# a, b, c = LI()


def LI(): return list(map(int, sys.stdin.buffer.readline().split()))

# a = I()


def I(): return int(sys.stdin.buffer.readline())

# abc def
# a, b = LS()


def LS(): return sys.stdin.buffer.readline().rstrip().decode('utf-8').split()

# a = S()


def S(): return sys.stdin.buffer.readline().rstrip().decode('utf-8')

# 2
# 1
# 2
# [1, 2]


def IR(n): return [I() for i in range(n)]

# 2
# 1 2 3
# 4 5 6
# [[1,2,3], [4,5,6]]


def LIR(n): return [LI() for i in range(n)]

# 2
# abc
# def
# [abc, def]


def SR(n): return [S() for i in range(n)]

# 2
# abc def
# ghi jkl
# [[abc,def], [ghi,jkl]]


def LSR(n): return [LS() for i in range(n)]

# 2
# abcd
# efgh
# [[a,b,c,d], [e,f,g,h]]


def SRL(n): return [list(S()) for i in range(n)]


def main():
    n, m = LI()
    # py = LIR(m)
    lst = [[] for i in range(n)]
    for i in range(m):
        p, y = map(int, input().split())
        lst[p - 1].append(y)

    for i in range(n):
        if len(lst[i]) > 1:
            lst[i].sort()

    for pair in py:
        print(str(pair[0]*1000000+lst[pair[0]-1].index(pair[1])+1).zfill(12))


if __name__ == "__main__":
    main()


Fixed submission:
# coding=utf-8
from math import floor, ceil, sqrt, factorial, log, gcd
from itertools import accumulate, permutations, combinations, product, combinations_with_replacement
from bisect import bisect_left, bisect_right
from collections import Counter, defaultdict
from heapq import heappop, heappush, heappushpop, heapify
import copy
import numpy as np
import sys
INF = float('inf')
mod = 10**9+7
sys.setrecursionlimit(10 ** 6)


def lcm(a, b): return a * b / gcd(a, b)

# 1 2 3
# a, b, c = LI()


def LI(): return list(map(int, sys.stdin.buffer.readline().split()))

# a = I()


def I(): return int(sys.stdin.buffer.readline())

# abc def
# a, b = LS()


def LS(): return sys.stdin.buffer.readline().rstrip().decode('utf-8').split()

# a = S()


def S(): return sys.stdin.buffer.readline().rstrip().decode('utf-8')

# 2
# 1
# 2
# [1, 2]


def IR(n): return [I() for i in range(n)]

# 2
# 1 2 3
# 4 5 6
# [[1,2,3], [4,5,6]]


def LIR(n): return [LI() for i in range(n)]

# 2
# abc
# def
# [abc, def]


def SR(n): return [S() for i in range(n)]

# 2
# abc def
# ghi jkl
# [[abc,def], [ghi,jkl]]


def LSR(n): return [LS() for i in range(n)]

# 2
# abcd
# efgh
# [[a,b,c,d], [e,f,g,h]]


def SRL(n): return [list(S()) for i in range(n)]


def main():
    n, m = LI()
    # py = LIR(m)
    lst = [[] for i in range(n)]
    ans = [0 for i in range(m)]

    for i in range(m):
        p, y = map(int, input().split())
        lst[p - 1].append((y, i))

    for i in range(n):
        if len(lst[i]) > 1:
            lst[i].sort()
        for j, pair in enumerate(lst[i]):
            ans[pair[1]] = str(i+1).zfill(6) + str(j + 1).zfill(6)

    for i in range(m):
        print(ans[i])


if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
# coding=utf-8
from math import floor, ceil, sqrt, factorial, log, gcd
from itertools import accumulate, permutations, combinations, product, combinations_with_replacement
from bisect import bisect_left, bisect_right
from collections import Counter, defaultdict
from heapq import heappop, heappush, heappushpop, heapify
import copy
import numpy as np
import sys
INF = float('inf')
mod = 10**9+7
sys.setrecursionlimit(10 ** 6)


def lcm(a, b): return a * b / gcd(a, b)

# 1 2 3
# a, b, c = LI()


def LI(): return list(map(int, sys.stdin.buffer.readline().split()))

# a = I()


def I(): return int(sys.stdin.buffer.readline())

# abc def
# a, b = LS()


def LS(): return sys.stdin.buffer.readline().rstrip().decode('utf-8').split()

# a = S()


def S(): return sys.stdin.buffer.readline().rstrip().decode('utf-8')

# 2
# 1
# 2
# [1, 2]


def IR(n): return [I() for i in range(n)]

# 2
# 1 2 3
# 4 5 6
# [[1,2,3], [4,5,6]]


def LIR(n): return [LI() for i in range(n)]

# 2
# abc
# def
# [abc, def]


def SR(n): return [S() for i in range(n)]

# 2
# abc def
# ghi jkl
# [[abc,def], [ghi,jkl]]


def LSR(n): return [LS() for i in range(n)]

# 2
# abcd
# efgh
# [[a,b,c,d], [e,f,g,h]]


def SRL(n): return [list(S()) for i in range(n)]


def main():
    n, m = LI()
    py = LIR(m)
    lst = [[] for i in range(n)]

    for pair in py:
        lst[pair[0] - 1].append(pair[1])

    for i in range(n):
        if len(lst[i]) > 1:
            lst[i].sort()

    for pair in py:
        print(str(pair[0]*1000000+lst[pair[0]-1].index(pair[1])+1).zfill(12))


if __name__ == "__main__":
    main()


Fixed submission:
# coding=utf-8
from math import floor, ceil, sqrt, factorial, log, gcd
from itertools import accumulate, permutations, combinations, product, combinations_with_replacement
from bisect import bisect_left, bisect_right
from collections import Counter, defaultdict
from heapq import heappop, heappush, heappushpop, heapify
import copy
import numpy as np
import sys
INF = float('inf')
mod = 10**9+7
sys.setrecursionlimit(10 ** 6)


def lcm(a, b): return a * b / gcd(a, b)

# 1 2 3
# a, b, c = LI()


def LI(): return list(map(int, sys.stdin.buffer.readline().split()))

# a = I()


def I(): return int(sys.stdin.buffer.readline())

# abc def
# a, b = LS()


def LS(): return sys.stdin.buffer.readline().rstrip().decode('utf-8').split()

# a = S()


def S(): return sys.stdin.buffer.readline().rstrip().decode('utf-8')

# 2
# 1
# 2
# [1, 2]


def IR(n): return [I() for i in range(n)]

# 2
# 1 2 3
# 4 5 6
# [[1,2,3], [4,5,6]]


def LIR(n): return [LI() for i in range(n)]

# 2
# abc
# def
# [abc, def]


def SR(n): return [S() for i in range(n)]

# 2
# abc def
# ghi jkl
# [[abc,def], [ghi,jkl]]


def LSR(n): return [LS() for i in range(n)]

# 2
# abcd
# efgh
# [[a,b,c,d], [e,f,g,h]]


def SRL(n): return [list(S()) for i in range(n)]


def main():
    n, m = LI()
    # py = LIR(m)
    lst = [[] for i in range(n)]
    ans = [0 for i in range(m)]

    for i in range(m):
        p, y = map(int, input().split())
        lst[p - 1].append((y, i))

    for i in range(n):
        if len(lst[i]) > 1:
            lst[i].sort()
        for j, pair in enumerate(lst[i]):
            ans[pair[1]] = str(i+1).zfill(6) + str(j + 1).zfill(6)

    for i in range(m):
        print(ans[i])


if __name__ == "__main__":
    main()