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 = input().strip()
chars = list(set(s))
chars.sort()
dic = {"a": 0,
       "b": 1,
       "c": 2,
       "d": 3,
       "e": 4,
       "f": 5,
       "g": 6,
       "h": 7,
       "i": 8,
       "j": 9,
       "k": 10,
       "l": 11,
       "m": 12,
       "n": 13,
       "o": 14,
       "p": 15,
       "q": 16,
       "r": 17,
       "s": 18,
       "t": 19,
       "u": 20,
       "v": 21,
       "w": 22,
       "x": 23,
       "y": 24,
       "z": 25
       }
swap = {v: k for k, v in dic.items()}
ans = "None"
count = 0
for c in chars:
    if dic[c] != count:
        ans = swap[count]
        break
    count += 1
if count != 25:
    print(swap[count])
else:
    print(ans)

Submission status: Runtime Error

Solution code:
alpha="abcdefghijklmnopqrstuvwxyz"
s=input()
s1=set(s)
s2=sorted(list(s1))
if len(alpha)>len(s2):
    a=list(alpha)
    for i in range(s2):
        a.remove(i)
    print(a[0])
    exit()
for i in range(len(alpha)):
    if s2[i]!=alpha[i]:
        print(alpha[i])
        exit()
print("None")

Submission status: Runtime Error

Solution code:
alpha="abcdefghijklmnopqrstuvwxyz"
s=input()
s1=set(s)
s2=sorted(list(s1))
for i in range(len(alpha)):
    if i==len(s2):
        if s2[i]=='a':
            print('b')
        else:
            print('a')
        break
    if s2[i]!=alpha[i]:
        print(alpha[i])
        exit()
print("None")

Submission status: Runtime Error

Solution code:
alpha="abcdefghijklmnopqrstuvwxyz"
s=input()
s1=set(s)
s2=sorted(list(s1))
for i in range(len(alpha)):
    if s2[i]!=alpha[i]:
        print(alpha[i])
        exit()
print("None")

Submission status: Runtime Error

Solution code:
str = input()
abc = ['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','aa']
i = 0
while abc[i] in str:
    if i <= 26:
        i += 1
    else:
        break

if i < 26:
    print(abc[i])
    
else:
    print("None")

Submission status: Runtime Error

Solution code:
str = input()
list = list(str)
abc = ['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']
i = 0
while abc[i] in str:
    i += 1

if i > 26:
    print(abc[i])
else:
    print("None")

Submission status: Runtime Error

Solution code:
str = input()
list = list(str)
abc = ['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']
i = 0
while abc[i] in str:
    i += 1

print(abc[i])

Submission status: Runtime Error

Solution code:
s=sorted(set(input()))
test="abcdefghijklmnopqrstuvwxyz"
for i in range(len(test)):
    if (s[i]!=test[i]):
        print(test[i])
        break
    if (s[i]==test[i] and i==len(s)-1 and i!=len(test)):
        print(test[i+1])
        break
else:
    print("None")

Submission status: Runtime Error

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

Submission status: Runtime Error

Solution code:
import string
alphabet = [chr(i) for i in range(97, 97+26)]
s = set(input())
result = set(alphabet) - s
result = sorted(list(result))
print(result[0])

Submission status: Runtime Error

Solution code:
s = set(list(str(input())))
s1=list(sorted(s))
t=0
if len(s1)==26:
    print(None)
for i in range(len(s1)+1):
    if not i+97==ord(s1[i]):
        print(chr(i+97))
        break

Submission status: Runtime Error

Solution code:
alp=['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']
s=list(input())
s_ = list(set(s))
#print(s)
#print(s_)
s.sort()
s_.sort()
#print(s)
#print(s_)
        
l=[]
cnt=0
for i in range(len(alp)):
            if s.count(alp[i]):a
                        pass
            else:
                        l.append(alp[i])
                        cnt+=1
#print(l)
if cnt==0:
            print('None')
else:
            print(min(l))
exit()

Submission status: Runtime Error

Solution code:
s = input()
b = [0]*25
for c in s:
  b[ord(c)-ord("a")]+=1
for i,c in enumerate(b):
  if c == 0:
    print(chr(i+ord("a")))
    exit()
print("None")

Submission status: Runtime Error

Solution code:
S=set(input())
alpha='abcdefghijklmnopqrstuvwxyz'
ans=sorted(set(alpha)^S)
print('None' if ans=='' else ans[0])

Submission status: Runtime Error

Solution code:
s = sorted(list(set(list(input()))))
i = 0
while i <= 25 and chr(i+97)==s[i]:
    i += 1
if i<=25:
    print(chr(i+97))
else:
    print("None")

Submission status: Runtime Error

Solution code:
N = str(input())
ans = "None"
for l in "abcdefghijklmnopqrstuvwxyz":
    if l not in N:
        ans = letter
        break
print(ans)

Submission status: Runtime Error

Solution code:
N = input()
ans = None
for l in "abcdefghijklmnopqrstuvwxyz":
    if l not in N:
        ans = letter
        break
print(ans)

Submission status: Runtime Error

Solution code:
s = input()
sa = [chr(i) for i in range(97, 97+26)], 
for i in list(set(s)):
  sa.remove(i)
print('None' if len(sa)==0 else sa[0])

Submission status: Runtime Error

Solution code:
s = input()
sa = [chr(i) for i in range(97, 97+26)], 
counter = [s.count(i) for i in sa]
print('None' if not 0 in counter else sa[counter.index(0)])

Submission status: Runtime Error

Solution code:
s = input()
sa, counter = [chr(i) for i in range(97, 97+26)], [s.count(i) for i in sa]
print('None' if not 0 in counter else sa[counter.index(0)])

Submission status: Runtime Error

Solution code:
s = input()
sa = [chr(i) for i in range(97, 97+26)]
ans= [i for i,x in enumerate(sa) if not x in s]
if ans == []:
  print(('None'))
print(sa[min(ans)])

Submission status: Runtime Error

Solution code:
S = input()
eng_list = [i for i in range(97, 123)]
for i in range(len(S)):
    for j in range(len(eng_list)):
        if ord(S[i]) == eng_list[j]:
            k = j
    eng_list.pop(k)
print(chr(eng_list[0])) if len(eng_list) != 0 else print("None")

Submission status: Runtime Error

Solution code:
import sys
lis = list('abcdefghijklmnopqrstuvwxyz')
s = sorted(set(input()))
for i in range(26):
    if s[i] != lis[i]:
        print(lis[i])
        sys.exit()
print("None")

Submission status: Runtime Error

Solution code:
S = input()

if len(set(S)) == 26:
  print("None")
else:
  for dam 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 not dam in list(set(S)):
           break
print(dam)

Submission status: Runtime Error

Solution code:
s=list(input())
if len(s)==26:
    print("None")
    exit()
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"]
s=set(s)
s=list(s)
s.sort()
for i in range(26):
    if a[i]!=s[i]:
        print(a[i])
        break
else:
    print("None")

Submission status: Runtime Error

Solution code:
s = set(input())
abc = set('abcdefghijklmnopqrstuvwxyz')
nots = abc.difference(s)
print(min(nots))

Submission status: Runtime Error

Solution code:
from string import ascii_lowercase
s=set(input())
print(sorted([x for x in ascii_lowercase if not x in s])[0])

Submission status: Runtime Error

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

Submission status: Runtime Error

Solution code:
S=list(input())
import string
X= list(string.ascii_lowercase)
for i in list:
    if i not in S:
        print(i)
        break

Submission status: Runtime Error

Solution code:
s=input()
alphabet = set([chr(i) for i in range(97, 97+26)])
x=set([s[i] for i in range(len(s))])
y=alphabet - x
z=list(y)
z.sort()
print(z[0])

Submission status: Runtime Error

Solution code:
s = str(input())
ABC= ["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"]
ans = "None"
for i in range(len(s)):
  if ABC[i] not in s:
    ans = ABC[i]
    break
print(ans)

Submission status: Runtime Error

Solution code:
s = str(input())
ABC= ["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"]
ans = "None"
for i in range(len(s)):
  if ABC[i] in s == False:
    ans = ABC[i]
    break
  else:
    pass
print(ans)

Submission status: Runtime Error

Solution code:
s = input()
a = ascii_lowercase

for i in a:
    if i not in s:
        print(i)
        break
    if i == "z":
        print("None")
        break

Submission status: Runtime Error

Solution code:
s = input()
a = ascii_lowercase

for i in range(len(a)):
    if a[i] not in s:
        print(a[i])
        break
    elif(i == 25):
        print("None")

Submission status: Runtime Error

Solution code:
import sys
s=list(input())
s=list(set(s))
s.sort()
#print(s)
for i in range(26):
    if chr(ord("a")+i)!=s[i]:
        print(chr(ord("a")+i))
        sys.exit()
print("None")

Submission status: Runtime Error

Solution code:
alpha = list("abcdefghijklmnopqrstuvwxyz")
s = input()

found = False
for chr in s:
    del alpha[alpha.index(chr)]

if len(alpha) == 0:
    print("None")
else:
    print(alpha[0])

Submission status: Runtime Error

Solution code:
S = input()
l = sorted(list(set(S)))

ans ="None"
number = [96]
for i in range(len(S)):
  if ord(l[i]) ==  number[-1] + 1:
    number.append(ord(l[i]))
  else:
    ans = chr(number[-1]+1)
    break

print(ans)

Submission status: Runtime Error

Solution code:
a = set(map(chr, range(ord(a), ord(z) + 1)))
b = set(input())
print('None' if a==b else sorted(a-b)[0])

Submission status: Runtime Error

Solution code:
a = set(range(ord(a), ord(z) + 1))
b = set([ord(i) for i in input()])
print('None' if a==b else chr(min(a-b)))

Submission status: Runtime Error

Solution code:
s=input()
lis=["q","w","e","r","t","y","u","i","o","p","l","k","j","h","g","f","d","s","a","z","x","c","v","b","n","m"]
a=set()
for i in range(len(s)):
    a.add(s[i])
#print(a)
ans=[]
for i in range(len(lis)):
    if lis[i] in a:
        continue
    ans.append(lis[i])
ans.sort()
print(ans[0])

Submission status: Runtime Error

Solution code:
s = input()

res = "abcdefghijklmnopqrstuvwxyz"

for i in range(len(s)):
    res = res.replace(s[i], "")
if len(s) == 0:
    print("None")
else:
    print(res[0])

Submission status: Runtime Error

Solution code:
S = list(set(list(input())))
S.sort()
al = 'abcdefghijklmnopqrstuvwxyz'
if len(S)==26:
  ans = 'None'
else:
  for i in range(len(al)):
    if al[i] != S[i]:
      ans = al[i]
      break
print(ans)

Submission status: Runtime Error

Solution code:
S = list(set(list(input())))
S.sort()
al = 'abcdefghijklmnopqrstuvwxyz'
for i in range(len(al)):
  if al[i] != S[i]:
    ans = al[i]
    break
if len(S)==26:
  ans = 'None'
print(ans)

Submission status: Runtime Error

Solution code:
s = input()
alp = [chr(i) for i in range(ord('a'),ord('z')+1)]
ans = []
for i in alp:
    if i not in s:
        ans.append(i)
ans.sort()
print(ans[0])

Submission status: Runtime Error

Solution code:
# -*- coding: utf-8 -*-
 
import math
import itertools
import sys
import copy
 
# 入力
#A, B, C, D = map(int, input().split())
#L = list(map(int, input().split()))
#N = int(input())
S = list(str(input()))
S.sort()
Q = "abcdefghijklmnopqrstuvwxyz"
#print (S)

index = 0
if S[0] == Q[0] :
  index += 1
else :
  print ("a")
  exit()

for i in range(1, len(S)) :
  if S[i] == Q[index] :
    index += 1
  else :
    if S[i] == S[i-1] :
      continue
    print (Q[index])
    exit()

if index != 26 :
  print (Q[index])
else :
  print ("None")

Submission status: Runtime Error

Solution code:
k=set("aqwertyuioplkjhgfdsazxcvbnm")
s=set(input())
ks=list(k-s)
if len(ks)==0:
  print("None")
else:
  ks.sort()
print(ks[0])

Submission status: Runtime Error

Solution code:
k=set("aqwertyuioplkjhgfdsazxcvbnm")
s=set(input())
ks=list(k-s)
ks.sort()
print(ks[0])

Submission status: Runtime Error

Solution code:
s = list(input())
s.sort()
start = ord('a')

for c in s:
    if ord(c) == start:
        continue
    elif ord(c) - start == 1:
        start+=1
        continue
    else:
        print(chr(start+1))
        exit()
print("None"

Submission status: Runtime Error

Solution code:
S = list(input())
alpha_list = [chr(i) for i in range(97,97+26)]

S = set(S)
alpha_list = set(alpha_list)
answer = alpha_list - S
answer = sorted(list(answer))[0]
print(answer)

Submission status: Runtime Error

Solution code:
S = input()

hoge = ['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']

hoge2 = list(S)

differlen = len((set(hoge) ^ set(hoge2)))

differ2 = set(hoge) ^ set(hoge3)
differ3 = sorted(differ2)




if differlen == 0:
    print("None")
else:
    print(differ3[0])

Submission status: Runtime Error

Solution code:
from collections import Counter
S = list(input())
S = Counter(S)
S = list(S.keys())
S.sort()
for i in range(26):
    alph = chr(ord("a") + i)
    #print(alph)
    if S[i] != chr(ord("a") + i):
        print(alph)
        exit()
print("None")

Submission status: Runtime Error

Solution code:
word = input()
al = [chr(ord("a") + i) for i in range(26)]
ans = "None"
for i in range(len(al)):
    if not al[i] in word:
      ans = append(al[i])
      break
print(ans)

Submission status: Runtime Error

Solution code:
s = input()

#文字列をリスト化
s = list(s)
s = set(s)
s = sorted(s)

#print(s)

t = 'abcdefghijklmnopqrstuvwxyz'
t = list(t)
#print(t)

if s == t:
	print('None')
else:
	for i in range(len(t)):
		if s[i]!=t[i]:
			print(t[i])
			break

Submission status: Runtime Error

Solution code:
x=input()
s=[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 s:
  if x.count(i)==0:
    print(i)
    exit()

Submission status: Runtime Error

Solution code:
def examB():
    St = S()
    AZ = [chr(i) for i in range(97, 97 + 26)]
    for s in AZ:
        if s not in St:
            ans = s
            break
    print(ans)

import sys
import copy
import bisect
import heapq
from collections import Counter,defaultdict,deque
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
def LS(): return sys.stdin.readline().split()
def S(): return sys.stdin.readline().strip()
mod = 10**9 + 7
inf = float('inf')

examB()

Submission status: Runtime Error

Solution code:
S = set(input())
Alp = "abcdefghijklmnopqrstuvwxyz"
L = []
for i in Alp:
    if i not in S:
        L.append(i)
if L == S:
    print("None")
else:
    print(min(L))

Submission status: Runtime Error

Solution code:
import string
alp=string.ascii_lowercase

s=input()
for i in range(28):
  temp=alp[i]
  if temp not in s:
    print(temp)
    exit()
print("None")

Submission status: Runtime Error

Solution code:
s = sorted(set(input()))

ans = "None"
for i in range(26):
    a = chr(ord("a") + i)
    if s[i] != a:
        ans = a
        break
print(ans)

Submission status: Runtime Error

Solution code:
import sys
S = input()
cnt = [False] * 30
for i in S:
    if i in "abcdefghijklmnopqrstuvwxyz"
        cnt[ord(i) - ord('a')] = True
 
for i in range(len(cnt)):
    if not cnt[i]:
        print(chr(ord('a')+i))
        sys.exit()
print("None")

Submission status: Runtime Error

Solution code:
import sys
S = input()
cnt = [False] * 30
for i in S:
    if i in "abcdefghijklmnopqrstuvwxyz"
    cnt[ord(i) - ord('a')] = True
 
for i in range(len(cnt)):
    if not cnt[i]:
        print(chr(ord('a')+i))
        sys.exit()
print("None")

Submission status: Runtime Error

Solution code:
S = input()
alphabet = "abcdefghijklmnopqrstuvwxyz"

for s in alphabet:
    if s not in S:
        print(s)
        sys.exit()

print("None")

Submission status: Runtime Error

Solution code:
import sys
S = input()
cnt = [0] * 26
for i in range(len(S)):
    cnt[ord(S[i]) - ord('a')] += 1

for i in range(len(S)):
    if not cnt[i]:
        print(chr(ord('a')+i))
        sys.exit()
print("None")

Submission status: Runtime Error

Solution code:
S = input()
cnt = [0] * 26
for i in range(len(S)):
    cnt[ord(S[i]) - ord('a')] += 1

for i in range(len(S)):
    if not cnt[i]:
        print(chr(ord('a')+i))
        break

Submission status: Runtime Error

Solution code:
s = set(input())
alpha = set(map(chr, range(97, 123)))

print(sorted(s^alpha)[0])

Submission status: Runtime Error

Solution code:
S=input()
s="abcdefghijklnmopqrstuvwxyz"
s = list(s)
  
for si in S:
  if si in s:
  	s.remove(si)
    
if s == "":
  print("None")
else:
  print(s[0])

Submission status: Runtime Error

Solution code:
S=input()
s="abcdefghijklmnopqrstucwxyz"

for si in s:
  if si in S
  	S.remove(si)
    
if S == "":
  print("None")
else:
  S.sort()
  print(S[0])

Submission status: Runtime Error

Solution code:
S = input()
k = []
ans = []
alphabet = ["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(len(S)):
  k.append(S[i])
k = sorted(k)
for i in range(26):
  if k[i] not in alphabet:
    ans.append(k[i])
print(ans[0])

Submission status: Runtime Error

Solution code:
a = input()
l=['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 len(set(a))==26:
  pritn('None')
else:
  for i in range(len(l)):
    if l[i] not in a:
      print(l[i])
      break

Submission status: Runtime Error

Solution code:
a = input()
l=['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 len(set(a))==26:
  pritn('None')
else:
  for i in range(len(l)):
    if l[i] not in a:
      print(l[i])
      exit()

Submission status: Runtime Error

Solution code:
a = input()
l=['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 len(set(a))=26:
  pritn('None')
  else:
    for i in range(len(l)):
      if l[i] not in a:
        print(l[i])
        exit()

Submission status: Runtime Error

Solution code:
import string
a = set(string.ascii_lowercase)
S = input()
if sorted(list((S))) == list(string.ascii_lowercase):
    print("None")
else:
    for i in set(S):
        if i in a:
            a.remove(i)
    print(sorted(list(a))[0])

Submission status: Runtime Error

Solution code:
import string
a = set(string.ascii_lowercase)
S = input()
if sorted(list((S))) == list(string.ascii_lowercase):
    print("None")
else:
    for i in set(S):
        if i in S:
            a.remove(i)
    print(sorted(list(a))[0])

Submission status: Runtime Error

Solution code:
s = list(input())
al = "abcdefghijklmnopqrstuvwxyz"
al = list(al)
li = []
for i in range(len(al)):
    if (al[i] not in s):
        li.append(al[i])
        
li.sort()
print(li[0])

Submission status: Runtime Error

Solution code:
S = input()

S_list = []
for s in S:
    if s not in S_list:
        S_list.append(s)

S_list.sort()

al_list = [chr(i) for i in range(97, 97+26)]

check_list = []
for i in range(26):
    if S_list[i] != al_list[i]:
        print(al_list[i])
        break
    else:
        check_list.append(True)

if len(check_list) == 26:
    print('None')

Submission status: Runtime Error

Solution code:
s = list(set(list(input())))
a = list("abcdefghijklmnopqrstuvwxyz")
for c in s:
  a.remove(c)
print(a[0])

Submission status: Runtime Error

Solution code:
s = list(input()).set
a = "abcdefghijklmnopqrstuvwxyz"
for c in s:
  a.remove(c)
print(a[0])

Submission status: Runtime Error

Solution code:
S = input()
S_list = list(set(S))
string = "qazwsxedcrfvtgbyhnujmikolp"
str_list = list(string)
str_list.sort()
for a in S_list:
    str_list.remove(a)
print(str_list.pop(0))

Submission status: Runtime Error

Solution code:
s = intput()
s.sort()
print(s[0])

Submission status: Runtime Error

Solution code:
S = input()

S = np.unique(sorted(S))

ans = 'None'
for ch in 'abcdefghijklmnopqrstuvwxyz':
  if ch in S:
    pass
  else:
    ans = ch
    break
print(ans)

Submission status: Runtime Error

Solution code:
s=set(list(input()))
print(s)
t='abcdefghijklmnopqrstuvwxyz'
for i in range(len(s)):
  if s[i]==t[i]:
    continue
  else:
    print(t[i])
    break

Submission status: Runtime Error

Solution code:
S = input()

import string

S = list(sorted(S))
T = string.ascii_lowercase

flag = False

for t in T:
    if t in S:
        flag = True
        continue
    else:
        flag = False
        print(a)
        break
        
if flag:
    print("None")

Submission status: Runtime Error

Solution code:
S = set(map(str, (input())))
s = list(S)
s.sort()
alphabet = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'z']
for i in range(len(s)-1):
    alphabet.remove(s[i])

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

Submission status: Runtime Error

Solution code:
S = set(list(input()))

for c in string.ascii_lowercase:
  if c not in S:
    print(c)
    exit()

print('None')

Submission status: Runtime Error

Solution code:
s=gets.chomp
26.times do |i|
  if !s.include?((97+i).chr)
    puts (97+i).chr
    exit
  end
end
puts "None"

Submission status: Runtime Error

Solution code:
import string
s = input()

s = sorted(set(s))
moji = [chr(i) for i in range(ord('a'), ord('z')+1)]
# print(s)
# print(moji)

def b():
    for i in range(len(moji)):
        if moji[i] != s[i]:
            return moji[i]
    return "None"

print(b())

Submission status: Runtime Error

Solution code:
s=sorted(set(input()))
A='abcdefghijklmnopqrstuvwxyz'
for i in range(s):
  if i not in A:
    print(s[i])
    break
print('None')

Submission status: Runtime Error

Solution code:
import sys
s=input()
A='abcdefghijklmnopqrstuvwxyz'
S=sorted(set(s))
for i in range(len(S)+1):
  if S[i]!=A[i]:
    print(A[i])
    sys.exit()
print('None')

Submission status: Runtime Error

Solution code:
import sys
s=input()
A='abcdefghijklmnopqrstuvwxyz'
S=sorted(set(s))
for i in range(len(S+1)):
  if S[i]!=A[i]:
    print(A[i])
    sys.exit()
print('None')

Submission status: Runtime Error

Solution code:
s = list(set(input()))
s.sort()
flag = False
for i in range(26):
    if s[i] != chr(ord('a') + i):
        flag = True
        print(chr(ord('a') + i))
        break
if flag == False:
    print('None')

Submission status: Runtime Error

Solution code:
for i in range(ord('a'), ord('z')+1):
  if chr(i) in s:
    print(chr(i))
    exit()
print('None')

Submission status: Runtime Error

Solution code:
for i in range(ord('a'), ord('z')+1):
  if chr(i) in s:
    print(chr(i))
    break
else:
  print('None')

Submission status: Runtime Error

Solution code:
s = input()
for i in range(ord('a'), ord('z')+1):
  if i in s:
    print(i)
    break
else:
  print('None')

Submission status: Runtime Error

Solution code:
alp=[chr(i) for i in range(97, 97+26)]
#文字コードで並び替える
#それぞれ一つずつにする
#print(alp)
s=sorted(set(list(input())))

for i in range(len(s)):
    if s[i]!=alp[i]:
        print(alp[i])
        break
    if i==len(s)-1:
        if len(s) != len(alp):
            print(alph[i+1])
        else:
            print("None")

Submission status: Runtime Error

Solution code:
letters="abcdefghijklmnopqrstuvwxyz"
ans=sorted(set(letters)^set(input)())
print("None" if len(ans)==0 else ans[0])

Submission status: Runtime Error

Solution code:
s=input()
for i in range(ord("a"),ord("z")+1):
  if chr(i) in s:
    print(chr(i))
    break
else:
  print("None)

Submission status: Runtime Error

Solution code:
s = list(input())
s = set(s)
alpha = set('abcdefghijklmnopqrstuvwxyz')
ans = sorted(alpha - s)
print(ans[0])

Submission status: Runtime Error

Solution code:
strings = list(input())
alfabet  = 'abcdefghijklmnopqrstuvwxyz'
for i in alfabet:
    if strings.count(i) <= 1:
        result = i
        break

print(result)

Submission status: Runtime Error

Solution code:
s = input()
all = "abcdefghijklmnopqrstuvwxyz"
ans = sorted(set(s)^set(all)) 
print("None" if ans == 0 else ans[0])

Submission status: Runtime Error

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

Submission status: Runtime Error

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

Submission status: Runtime Error

Solution code:
print(min(set(map(chr, range(97, 123))) - set(input())))

Submission status: Runtime Error

Solution code:
S = input()

li = [chr(i) for i in range(ord("a"), ord("z") + 1)]

for i in range(len(S)):
  if S[i] in li:
    li.remove(S[i])
print (li[0])

Submission status: Runtime Error

Solution code:
s = [char(i) for i in range(97,97+26)]
print(s)

Submission status: Runtime Error

Solution code:
S = input()
S = sorted(S)
i = 0
if S[0] != "a":
    print("a")
    exit(1)
while i<len(S)-1:
    if ord(S[i]) == ord(S[i+1]) or ord(S[i]) == ord(S[i+1])-1:
        i += 1
    else:
        print(chr(ord(S[i])+1))
        exit(0)

if S[-1] == "z":
    print("None")
else:
    print(chr(ord(S[i])+1))

Submission status: Runtime Error

Solution code:
S = input()
alpha = [chr(ord('a') + i) for i in range(26)]
n=0
c=0
while c == 0 or n < 26:
  if alpha[n] in S:
    c = n
  n+=1
if c == 0:
  print('None')
else:
  print(alpha[n])

Submission status: Runtime Error

Solution code:
s = input()
t = set()
for i in range(len(s)):
  t.add(s[i])
o = list(t)
o.sort()
u = 'qwertyuiopasdfghjklzxcvbnm'
v = []
for i in range(len(u)):
  v.append(u[i])
v.sort()
now = 0
if len(o) == 26:
  print('None')
else:
  for i in range(26):
    if o[i] == v[i]:
      now += 1
    else:
      print(v[now])
      break

Submission status: Runtime Error

Solution code:
s = input()
t = set()
for i in range(len(s)):
  t.add(s[i])
o = list(t)
o.sort()
u = 'qwertyuiopasdfghjklzxcvbnm'
v = []
for i in range(len(u)):
  v.append(u[i])
v.sort()
now = 0
for i in range(26):
  if o[i] == v[i]:
    now += 1
  else:
    print(v[now])
    break
else:
  print('None')

Submission status: Runtime Error

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

for s in text:
    alphabet = alphabet.replace(s, '')

if alphabet is False:
    print('None')
else:
    print(alphabet[0])

Submission status: Runtime Error

Solution code:
s = input()
s =input()
ab = [chr(97+i) for i in range(26)]
res = 'None'
for i in ab:
    if i not in s:
        res = i
        break
print(res)

Submission status: Runtime Error

Solution code:
s = list(set(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"]
li = []
for i in range(len(s)):
  if s[i] not in a:
    li.append(s[i])
print(min(li))

Submission status: Runtime Error

Solution code:
S = input()
str = "abcdefghijklmnopqrstuvwxyz"
l1 = list(str)
l2 = list(S)
l3 = list(set(l1)-set(l2))
l3.sort()
print(l3[0])

Submission status: Runtime Error

Solution code:
s = input()
s = [ord(ss) in ss in s]
flag = False
for i in range(ord('a'), ord('z')+1):
  if i in s:
    flag = True
    ans = chr(i)
if flag:
  print(ans)
else:
  print('None')

Submission status: Runtime Error

Solution code:
s = list(input())
s = list(set(s))
s.sort()
print('s:', s)
ans = 'a'
cnt = 0
while True:
    if cnt == 26:
        print(None)
        break
    else:
        if s[cnt] != ans:
            print(ans)
            break
        else:
            ans = chr(ord(ans)+1)
            cnt += 1

Submission status: Runtime Error

Solution code:
s = list(input())
s = list(set(s))
s.sort()
ans = 'a'
cnt = 0
while True:
    if cnt == 26:
        print('None')
        break
    else:
        if s[cnt] != ans:
            print(ans)
            break
        else:
            ans = chr(ord(ans)+1)
            cnt += 1

Submission status: Runtime Error

Solution code:
s = list(input())
s = list(set(s))
s.sort()
ans = 'a'
cnt = 0
while True:
    if s[cnt] != ans:
        print(ans)
        break
    else:
        ans = chr(ord(ans)+1)
        cnt += 1
    if cnt == 26:
        print('None')
        break

Submission status: Runtime Error

Solution code:
a = [False for i in range(26)]
b = input()
for c in b :
  a[c-'a'] += 1
for i, boo in a :
  if not boo : 
    print('a'+ i)
    break

Submission status: Runtime Error

Solution code:
S = list(input())
s = set(S)
S = list(s)
S.sort()
if len(S) == 26:
    print (None)
else:
    tmp = 0
    for i in 'abcdefghijklmnopqrstuvwxyz':
        if i == S[tmp]:
            tmp += 1
        else:
            print (i)
            break

Submission status: Runtime Error

Solution code:
import string

s = input()
letters = string.ascii_lowercase
hash = {}

for chara in s:
  hash[chara] = 1
  if(hash.keys().count() == 26):
    print("None")
    exit()

for c in letters:
  if c not in hash:
    print(c)
    exit()

Submission status: Runtime Error

Solution code:
#include <bits/stdc++.h>
using namespace std;
#define rep(i,N) for(int i=0,i##_max=(N);i<i##_max;++i)
#define repp(i,l,r) for(int i=(l),i##_max=(r);i<i##_max;++i)
#define per(i,N) for(int i=(N)-1;i>=0;--i)
#define perr(i,l,r) for(int i=r-1,i##_min(l);i>=i##_min;--i)
#define all(arr) (arr).begin(), (arr).end()
#define SP << " " <<
#define SPF << " "
#define SPEEDUP cin.tie(0);ios::sync_with_stdio(false);
#define MAX_I INT_MAX //1e9
#define MIN_I INT_MIN //-1e9
#define MAX_UI UINT_MAX //1e9
#define MAX_LL LLONG_MAX //1e18
#define MIN_LL LLONG_MIN //-1e18
#define MAX_ULL ULLONG_MAX //1e19
  typedef long long ll;
  typedef pair<int,int> PII;
  typedef pair<char,char> PCC;
  typedef pair<ll,ll> PLL;
  typedef pair<char,int> PCI;
  typedef pair<int,char> PIC;
  typedef pair<ll,int> PLI;
  typedef pair<int,ll> PIL; 
  typedef pair<ll,char> PLC; 
  typedef pair<char,ll> PCL; 

inline void YesNo(bool b){ cout << (b?"Yes" : "No") << endl;}
inline void YESNO(bool b){ cout << (b?"YES" : "NO") << endl;}
inline void Yay(bool b){ cout << (b?"Yay!" : ":(") << endl;}

int main(void){
  SPEEDUP
  cout << setprecision(15);
  string s;cin >> s;
  sort(all(s));
  s.erase(unique(all(s)),s.end());
  bool isNone = true;
  rep(i,26){
    char out = 'a'+i;
    if(i==s.length()){
      cout << out << endl;
      isNone = false;
      break;
    }
    if(s[i] != 'a'+i){
      cout << out << endl;
      isNone = false;
      break;
    }
  }
  if(isNone) cout << "None" << endl;
  return 0;
}

Submission status: Runtime Error

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

s_set = set(s)
if len(s_set) == 26:
    print('None')
else:
    s_sorted = sorted(s_set)
    for i, a in enumerate(alpha):
        if a != s_sorted[i]:
            print(a)
            break

Submission status: Runtime Error

Solution code:
s = input()
check = "abcdefghijklmnopqrstuvwxyz"
ans =   sorted(set(s)^set(check))
print("None" if ans == 0 else ans[0])

Submission status: Runtime Error

Solution code:
S = input()
A = [chr(ord('a') + i) for i in range(26)]
c = 0

for i in range(26):
  if A[i] in S:
    continue
  else:
    print(A[i])
    c = 1
    break
if c = 0:
  print("None")