Buggy python submission (verdict: Runtime Error):
def solve():
  k = int(input())
  list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 21, 22, 23, 32, 33, 34, 43, 44, 45, 54, 55, 56, 65, 66, 67, 76, 77, 78, 87, 88, 89, 98, 99, 100, 101, 110, 111, 112, 121, 122, 123, 210, 211, 212, 221, 222, 223, 232, 233, 234, 321, 322, 323, 332, 333, 334, 343, 344, 345, 432, 433, 434, 443, 444, 445, 454, 455, 456, 543, 544, 545, 554, 555, 556, 565, 566, 567, 654, 655, 656, 665, 666, 667, 676, 677, 678, 765, 766, 767, 776, 777, 778, 787, 788, 789, 876, 877, 878, 887, 888, 889, 898, 899, 987, 988, 989, 998, 999, 1000, 1001, 1010, 1011, 1012, 1100, 1101, 1110, 1111, 1112, 1121, 1122, 1123, 1210, 1211, 1212, 1221, 1222, 1223, 1232, 1233, 1234, 2100, 2101, 2110, 2111, 2112, 2121, 2122, 2123, 2210, 2211, 2212, 2221, 2222, 2223, 2232, 2233, 2234, 2321, 2322, 2323, 2332, 2333, 2334, 2343, 2344, 2345, 3210, 3211, 3212, 3221, 3222, 3223, 3232, 3233, 3234, 3321, 3322, 3323, 3332, 3333, 3334, 3343, 3344, 3345, 3432, 3433, 3434, 3443, 3444, 3445, 3454, 3455, 3456, 4321, 4322, 4323, 4332, 4333, 4334, 4343, 4344, 4345, 4432, 4433, 4434, 4443, 4444, 4445, 4454, 4455, 4456, 4543, 4544, 4545, 4554, 4555, 4556, 4565, 4566, 4567, 5432, 5433, 5434, 5443, 5444, 5445, 5454, 5455, 5456, 5543, 5544, 5545, 5554, 5555, 5556, 5565, 5566, 5567, 5654, 5655, 5656, 5665, 5666, 5667, 5676, 5677, 5678, 6543, 6544, 6545, 6554, 6555, 6556, 6565, 6566, 6567, 6654, 6655, 6656, 6665, 6666, 6667, 6676, 6677, 6678, 6765, 6766, 6767, 6776, 6777, 6778, 6787, 6788, 6789, 7654, 7655, 7656, 7665, 7666, 7667, 7676, 7677, 7678, 7765, 7766, 7767, 7776, 7777, 7778, 7787, 7788, 7789, 7876, 7877, 7878, 7887, 7888, 7889, 7898, 7899, 8765, 8766, 8767, 8776, 8777, 8778, 8787, 8788, 8789, 8876, 8877, 8878, 8887, 8888, 8889, 8898, 8899, 8987, 8988, 8989, 8998, 8999, 9876, 9877, 9878, 9887, 9888, 9889, 9898, 9899, 9987, 9988, 9989, 9998, 9999, 10000, 10001, 10010, 10011, 10012, 10100, 10101, 10110, 10111, 10112, 10121, 10122, 10123, 11000, 11001, 11010, 11011, 11012, 11100, 11101, 11110, 11111, 11112, 11121, 11122, 11123, 11210, 11211, 11212, 11221, 11222, 11223, 11232, 11233, 11234, 12100, 12101, 12110, 12111, 12112, 12121, 12122, 12123, 12210, 12211, 12212, 12221, 12222, 12223, 12232, 12233, 12234, 12321, 12322, 12323, 12332, 12333, 12334, 12343, 12344, 12345, 21000, 21001, 21010, 21011, 21012, 21100, 21101, 21110, 21111, 21112, 21121, 21122, 21123, 21210, 21211, 21212, 21221, 21222, 21223, 21232, 21233, 21234, 22100, 22101, 22110, 22111, 22112, 22121, 22122, 22123, 22210, 22211, 22212, 22221, 22222, 22223, 22232, 22233, 22234, 22321, 22322, 22323, 22332, 22333, 22334, 22343, 22344, 22345, 23210, 23211, 23212, 23221, 23222, 23223, 23232, 23233, 23234, 23321, 23322, 23323, 23332, 23333, 23334, 23343, 23344, 23345, 23432, 23433, 23434, 23443, 23444, 23445, 23454, 23455, 23456, 32100, 32101, 32110, 32111, 32112, 32121, 32122, 32123, 32210, 32211, 32212, 32221, 32222, 32223, 32232, 32233, 32234, 32321, 32322, 32323, 32332, 32333, 32334, 32343, 32344, 32345, 33210, 33211, 33212, 33221, 33222, 33223, 33232, 33233, 33234, 33321, 33322, 33323, 33332, 33333, 33334, 33343, 33344, 33345, 33432, 33433, 33434, 33443, 33444, 33445, 33454, 33455, 33456, 34321, 34322, 34323, 34332, 34333, 34334, 34343, 34344, 34345, 34432, 34433, 34434, 34443, 34444, 34445, 34454, 34455, 34456, 34543, 34544, 34545, 34554, 34555, 34556, 34565, 34566, 34567, 43210, 43211, 43212, 43221, 43222, 43223, 43232, 43233, 43234, 43321, 43322, 43323, 43332, 43333, 43334, 43343, 43344, 43345, 43432, 43433, 43434, 43443, 43444, 43445, 43454, 43455, 43456, 44321, 44322, 44323, 44332, 44333, 44334, 44343, 44344, 44345, 44432, 44433, 44434, 44443, 44444, 44445, 44454, 44455, 44456, 44543, 44544, 44545, 44554, 44555, 44556, 44565, 44566, 44567, 45432, 45433, 45434, 45443, 45444, 45445, 45454, 45455, 45456, 45543, 45544, 45545, 45554, 45555, 45556, 45565, 45566, 45567, 45654, 45655, 45656, 45665, 45666, 45667, 45676, 45677, 45678, 54321, 54322, 54323, 54332, 54333, 54334, 54343, 54344, 54345, 54432, 54433, 54434, 54443, 54444, 54445, 54454, 54455, 54456, 54543, 54544, 54545, 54554, 54555, 54556, 54565, 54566, 54567, 55432, 55433, 55434, 55443, 55444, 55445, 55454, 55455, 55456, 55543, 55544, 55545, 55554, 55555, 55556, 55565, 55566, 55567, 55654, 55655, 55656, 55665, 55666, 55667, 55676, 55677, 55678, 56543, 56544, 56545, 56554, 56555, 56556, 56565, 56566, 56567, 56654, 56655, 56656, 56665, 56666, 56667, 56676, 56677, 56678, 56765, 56766, 56767, 56776, 56777, 56778, 56787, 56788, 56789, 65432, 65433, 65434, 65443, 65444, 65445, 65454, 65455, 65456, 65543, 65544, 65545, 65554, 65555, 65556, 65565, 65566, 65567, 65654, 65655, 65656, 65665, 65666, 65667, 65676, 65677, 65678, 66543, 66544, 66545, 66554, 66555, 66556, 66565, 66566, 66567, 66654, 66655, 66656, 66665, 66666, 66667, 66676, 66677, 66678, 66765, 66766, 66767, 66776, 66777, 66778, 66787, 66788, 66789, 67654, 67655, 67656, 67665, 67666, 67667, 67676, 67677, 67678, 67765, 67766, 67767, 67776, 67777, 67778, 67787, 67788, 67789, 67876, 67877, 67878, 67887, 67888, 67889, 67898, 67899, 76543, 76544, 76545, 76554, 76555, 76556, 76565, 76566, 76567, 76654, 76655, 76656, 76665, 76666, 76667, 76676, 76677, 76678, 76765, 76766, 76767, 76776, 76777, 76778, 76787, 76788, 76789, 77654, 77655, 77656, 77665, 77666, 77667, 77676, 77677, 77678, 77765, 77766, 77767, 77776, 77777, 77778, 77787, 77788, 77789, 77876, 77877, 77878, 77887, 77888, 77889, 77898, 77899, 78765, 78766, 78767, 78776, 78777, 78778, 78787, 78788, 78789, 78876, 78877, 78878, 78887, 78888, 78889, 78898, 78899, 78987, 78988, 78989, 78998, 78999, 87654, 87655, 87656, 87665, 87666, 87667, 87676, 87677, 87678, 87765, 87766, 87767, 87776, 87777, 87778, 87787, 87788, 87789, 87876, 87877, 87878, 87887, 87888, 87889, 87898, 87899, 88765, 88766, 88767, 88776, 88777, 88778, 88787, 88788, 88789, 88876, 88877, 88878, 88887, 88888, 88889, 88898, 88899, 88987, 88988, 88989, 88998, 88999, 89876, 89877, 89878, 89887, 89888, 89889, 89898, 89899, 89987, 89988, 89989, 89998, 89999, 98765, 98766, 98767, 98776, 98777, 98778, 98787, 98788, 98789, 98876, 98877, 98878, 98887, 98888, 98889, 98898, 98899, 98987, 98988, 98989, 98998, 98999, 99876, 99877, 99878, 99887, 99888, 99889, 99898, 99899, 99987, 99988, 99989, 99998, 99999]
  print(list[k-1])
  return 0
 
if __name__ == "__main__":
  solve()

Fixed submission:
import numpy as np
import math
import collections
import fractions
import itertools

def rec(d, val, all):
    all.append(val)
    if d >= 10:
        return
    for j in range(-1, 2):
        add = val % 10 + j
        if add >= 0 and add <= 9:
            rec(d+1, val*10+add, all)

def solve():
    k = int(input())
    all = []
    for i in range(1,10):
        rec(1, i, all)
    all.sort()
    print(all[k-1])
    return 0

if __name__ == "__main__":
    solve()