Vanya got an important task — he should enumerate books in the library and label each book with its number. Each of the *n* books should be assigned with a number from 1 to *n*. Naturally, distinct books should be assigned distinct numbers.

Vanya wants to know how many digits he will have to write down as he labels the books.
The first line contains integer *n* (1 ≤ *n* ≤ 10<sup class="upper-index">9</sup>) — the number of books in the library.
a=[1,2,3,4,5,6,7,8,9,10]
aa=[9,90,900,9000,90000,900000,9000000,90000000,900000000,9000000000]

n=int(input())
i=0
ans=0
while(n>0):
    if n>=aa[i]:
        ans+=(a[i]*aa[i])
        
        n=n-aa[i]
        i+=1
    else:
        ans+=(n)*a[i]
        n=0
print(ans)
        
    
