Buggy python submission (verdict: Time Limit Exceeded):
import sys
sys.setrecursionlimit(20000000)

s = input()
K = int(input())


def calculate(str, k):
    s = sorted(list(set(str)))
    criteron = s[:k]
    objs = {}
    for index, s in enumerate(str):
        if s in criteron:
            for i in range(index+1,len(str)+1):
                objs.__setitem__(str[index:i],True)

    arr = sorted(objs.keys())

    print(arr[k-1])

calculate(s, K)


Fixed submission:
import sys
sys.setrecursionlimit(20000000)

s = input()
K = int(input())


def calculate(str, k):
    s = sorted(list(set(str)))
    criteron = s[:k]
    objs = {}
    for index, s in enumerate(str):
        if s in criteron:
            if len(str)+1 > index + 1 + k:
                made = index + 1 + k
            else:
                made = len(str)+1
            for i in range(index+1,made):
                objs.__setitem__(str[index:i],True)

    arr = sorted(objs.keys())

    print(arr[k-1])

calculate(s, K)

Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(20000000)

s = input()
K = int(input())


def calculate(str, k):
    if len(str) > 5:
        criterion = ["a", "b", "c", "d", "e"]
    else:
        criterion = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t",
                     "u", "v", "w", "x", "y", "z"]
    objs = {}
    for index, s in enumerate(str):
        if s in criterion:
            for i in range(index+1,len(str)+1):
                objs.__setitem__(str[index:i],True)

    arr = sorted(objs.keys())

    print(arr[k-1])

calculate(s, K)


Fixed submission:
import sys
sys.setrecursionlimit(20000000)

s = input()
K = int(input())


def calculate(str, k):
    s = sorted(list(set(str)))
    criteron = s[:k]
    objs = {}
    for index, s in enumerate(str):
        if s in criteron:
            if len(str)+1 > index + 1 + k:
                made = index + 1 + k
            else:
                made = len(str)+1
            for i in range(index+1,made):
                objs.__setitem__(str[index:i],True)

    arr = sorted(objs.keys())

    print(arr[k-1])

calculate(s, K)

Buggy python submission (verdict: Runtime Error):
s = input()
K = int(input())


def calculate(str, k):
    if len(str) > 5:
        criterion = ["a", "b", "c", "d", "e"]
    else:
        criterion = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t",
                     "u", "v", "w", "x", "y", "z"]

    objs = {}
    for index, s in enumerate(str):
        if s in criterion:
            for i in range(index+1,len(str)+1):
                objs.__setitem__(str[index:i],True)

    arr = sorted(objs.keys())

    print(arr[k-1])

calculate(s, K)


Fixed submission:
import sys
sys.setrecursionlimit(20000000)

s = input()
K = int(input())


def calculate(str, k):
    s = sorted(list(set(str)))
    criteron = s[:k]
    objs = {}
    for index, s in enumerate(str):
        if s in criteron:
            if len(str)+1 > index + 1 + k:
                made = index + 1 + k
            else:
                made = len(str)+1
            for i in range(index+1,made):
                objs.__setitem__(str[index:i],True)

    arr = sorted(objs.keys())

    print(arr[k-1])

calculate(s, K)

Buggy python submission (verdict: Runtime Error):
s = input()
K = int(input())


def calculate(s, k):
    if len(s) > 5:
        ignoreCriterion = ["f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x",
                           "y", "z"]
    else:
        ignoreCriterion = []

    length = len(s)

    objs = {}
    for i in range(1, length + 1):
        for j in range(0, length + 1 - i):
            if s[j] in ignoreCriterion:
                continue
            objs.__setitem__(s[j:j + i], True)

    s = sorted(objs.keys())

    print(s[k-1])


calculate(s, K)

Fixed submission:
import sys
sys.setrecursionlimit(20000000)

s = input()
K = int(input())


def calculate(str, k):
    s = sorted(list(set(str)))
    criteron = s[:k]
    objs = {}
    for index, s in enumerate(str):
        if s in criteron:
            if len(str)+1 > index + 1 + k:
                made = index + 1 + k
            else:
                made = len(str)+1
            for i in range(index+1,made):
                objs.__setitem__(str[index:i],True)

    arr = sorted(objs.keys())

    print(arr[k-1])

calculate(s, K)

Buggy python submission (verdict: Time Limit Exceeded):
s = input()
K = int(input())

def calculate(s,k):
    length = len(s)

    objs = {}
    for i in range(1,length+1):
        for j in range(0,length +1 - i):
            objs.__setitem__(s[j:j+i],True)

    s = sorted(objs.keys())

    print(s[k-1])


calculate(s,K)

Fixed submission:
import sys
sys.setrecursionlimit(20000000)

s = input()
K = int(input())


def calculate(str, k):
    s = sorted(list(set(str)))
    criteron = s[:k]
    objs = {}
    for index, s in enumerate(str):
        if s in criteron:
            if len(str)+1 > index + 1 + k:
                made = index + 1 + k
            else:
                made = len(str)+1
            for i in range(index+1,made):
                objs.__setitem__(str[index:i],True)

    arr = sorted(objs.keys())

    print(arr[k-1])

calculate(s, K)