快進撃Atcoder#4

ARC127に参加した！

結果は０完

終わってからも粘ってA問題　leading 1s を解いたらACできた！

N = int(input())
strN = str(N)
count = 0

for _ in range(len(strN)):
   if strN[0] !="1" and len(strN) != 1:
       for i in range(1,len(str(N))+1):
           count += (10**(len(str(N))-i))*i
       break
   elif strN == "0":
       break
   elif len(strN) == 1:
       count += 1
       break
   elif strN[0] == "1":
       if strN[1] != "0":
           N = N - 10**(len(strN)-1)
           strN = str(N)
           count += int(strN) + 1
           for i in range(1,len(str(N))+1):
               count += (10**(len(str(N))-i))
       else:
           sstrN = strN
           N = N - 10**(len(strN)-1)
           strN = str(N)
           count += int(strN) + 1

           NN = N + 9*(10**(len(sstrN)-2))
           strNN = str(NN)
           
           for i in range(1,len(str(NN))+1):
               count += (10**(len(str(NN))-i))*i
           break
           
print(count)