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

l =[]

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

l2 = []
for x in l:
    if x not in l2:
        l2.append(x)

ans = l2[K - 1]

print(ans)


Fixed submission:
s = list(input())
K = int(input())

l =[]

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

l2 = []
for x in l:
    if len(l2) > 6:
        break
    if x not in l2:
        l2.append(x)


ans = l2[K - 1]

print(ans)

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

l =[]
l2 = []

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

for i in l:
    is_double = 0
    for j in l2:
        if j == i:
            is_double = 1
            break
    if is_double == 0:
        l2.append(i)

ans = l2[K - 1]

print(ans)


Fixed submission:
s = list(input())
K = int(input())

l =[]

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

l2 = []
for x in l:
    if len(l2) > 6:
        break
    if x not in l2:
        l2.append(x)


ans = l2[K - 1]

print(ans)

Buggy python submission (verdict: Runtime Error):
s = list(input())
K = int(input())
l = []
l2 = []
l3 = []
l4 = []

for i in range(len(s)):
    s[i] = str(ord(s[i])-ord("a")+11)

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        tmp += s[j]
        if(len(tmp)<6):
            l.append(tmp)


for i in range(len(l)):
    while True:
        if len(l[i]) == len(s)*2: break
        l[i] += '0'

for i in l:
    is_multi = 0
    i = int(i)
    for j in l2:
        if i == j:
            is_multi = 1
            break
    if is_multi == 0:
        l2.append(i)

l2.sort()

l2 = list(str(l2[K-1]))

tmp = ''
for i in range(len(l2)):
    if l2[i] != '0':
        tmp += l2[i]

l3 = list(tmp)
if len(l3) % 2 == 1:
    l3.append('0')

i = 0
while i < len(l3):
    tmp = chr(int(l3[i] + l3[i+1]) - 11 + ord('a'))
    l4.append(tmp)
    i += 2

ans =''
for i in range(len(l4)):
    ans += l4[i]

print(ans)


Fixed submission:
s = list(input())
K = int(input())

l =[]

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

l2 = []
for x in l:
    if len(l2) > 6:
        break
    if x not in l2:
        l2.append(x)


ans = l2[K - 1]

print(ans)

Buggy python submission (verdict: Runtime Error):
s = list(input())
K = int(input())
l = []
l2 = []
l3 = []
l4 = []

for i in range(len(s)):
    s[i] = str(ord(s[i])-ord("a")+11)

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        tmp += s[j]
        l.append(tmp)

for i in range(len(l)):
    while True:
        if len(l[i]) == len(s)*2: break
        l[i] += '0'

for i in l:
    is_multi = 0
    i = int(i)
    for j in l2:
        if i == j:
            is_multi = 1
    if is_multi == 0:
        l2.append(i)

l2.sort()

l2 = list(str(l2[K-1]))

tmp = ''
for i in range(len(l2)):
    if l2[i] != '0':
        tmp += l2[i]

l3 = list(tmp)
if len(l3) % 2 == 1:
    l3.append('0')

i = 0
while i < len(l3):
    tmp = chr(int(l3[i] + l3[i+1]) - 11 + ord('a'))
    l4.append(tmp)
    i += 2

ans =''
for i in range(len(l4)):
    ans += l4[i]


print(ans)


Fixed submission:
s = list(input())
K = int(input())

l =[]

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

l2 = []
for x in l:
    if len(l2) > 6:
        break
    if x not in l2:
        l2.append(x)


ans = l2[K - 1]

print(ans)

Buggy python submission (verdict: Runtime Error):
s = list(input())
K = int(input())
l = []
l2 = []
l3 = []
l4 = []

for i in range(len(s)):
    s[i] = str(ord(s[i])-ord("a")+11)

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        tmp += s[j]
        l.append(tmp)

for i in range(len(l)):
    while True:
        if len(l[i]) == len(s)*2: break
        l[i] += '0'

for i in l:
    is_multi = 0
    i = int(i)
    for j in l2:
        if i == j:
            is_multi = 1
    if is_multi == 0:
        l2.append(i)

l2.sort()

l2 = list(str(l2[K-1]))

tmp = ''
for i in range(len(l2)):
    if l2[i] != '0':
        tmp += l2[i]

l3 = list(tmp)
if len(l3) % 2 == 1:
    l3.append('0')

i = 0
while i < len(l3)-1:
    tmp = chr(int(l3[i] + l3[i+1]) - 11 + ord('a'))
    l4.append(tmp)
    i += 2

ans =''
for i in range(len(l4)):
    ans += l4[i]


print(ans)


Fixed submission:
s = list(input())
K = int(input())

l =[]

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

l2 = []
for x in l:
    if len(l2) > 6:
        break
    if x not in l2:
        l2.append(x)


ans = l2[K - 1]

print(ans)

Buggy python submission (verdict: Runtime Error):
s = list(input())
K = int(input())
l = []
l2 = []
l3 = []
l4 = []

for i in range(len(s)):
    s[i] = str(ord(s[i])-ord("a")+11)

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        tmp += s[j]
        l.append(tmp)

for i in range(len(l)):
    while True:
        if len(l[i]) == len(s)*2: break
        l[i] += '0'

for i in l:
    is_multi = 0
    i = int(i)
    for j in l2:
        if i == j:
            is_multi = 1
    if is_multi == 0:
        l2.append(i)

l2.sort()

l2 = list(str(l2[K-1]))

tmp = ''
for i in range(len(l2)):
    if l2[i] != '0':
        tmp += l2[i]

l3 = list(tmp)

i = 0
while i < len(l3):
    tmp = chr(int(l3[i] + l3[i+1]) - 11 + ord('a'))
    l4.append(tmp)
    i += 2

ans =''
for i in range(len(l4)):
    ans += l4[i]


print(ans)


Fixed submission:
s = list(input())
K = int(input())

l =[]

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

l2 = []
for x in l:
    if len(l2) > 6:
        break
    if x not in l2:
        l2.append(x)


ans = l2[K - 1]

print(ans)

Buggy python submission (verdict: Runtime Error):
s = list(input())
K = int(input())
l = []
l2 = []
l3 = []
l4 = []

for i in range(len(s)):
    s[i] = str(ord(s[i])-ord("a")+11)

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        tmp += s[j]
        l.append(tmp)

for i in range(len(l)):
    while True:
        if len(l[i]) == len(s)*2: break
        l[i] += '0'

for i in l:
    is_multi = 0
    i = int(i)
    for j in l2:
        if i == j:
            is_multi = 1
    if is_multi == 0:
        l2.append(i)

l2.sort()
l2 = list(str(l2[K]))

tmp = ''
for i in range(len(l2)):
    if l2[i] != '0':
        tmp += l2[i]

l3 = list(tmp)

i = 0
while i < len(l3):
    tmp = chr(int(l3[i] + l3[i+1]) - 11 + ord('a'))
    l4.append(tmp)
    i += 2

ans =''
for i in range(len(l4)):
    ans += l4[i]


print(ans)


Fixed submission:
s = list(input())
K = int(input())

l =[]

for i in range(len(s)):
    tmp = ''
    for j in range(i, len(s)):
        if j > i + 4: break
        tmp += s[j]
        l.append(tmp)
l.sort()

l2 = []
for x in l:
    if len(l2) > 6:
        break
    if x not in l2:
        l2.append(x)


ans = l2[K - 1]

print(ans)