Task

Vanya gets bored one day and decides to enumerate a large pile of rocks. He first counts the rocks and finds out that he has n rocks in the pile, then he goes to the store to buy labels for enumeration.

Each of the labels is a digit from 0 to 9 and each of the n rocks should be assigned a unique number from 1 to n.

If each label costs $1, how much money will Vanya spend on this project?

Input/Output

• [input] integer n

The number of rocks in the pile.

1  ≤  n  ≤  10^9

• [output] an integer

the cost of the enumeration.

Example

For n = 13, the result should be 17.

the numbers from 1 to n are:
1 2 3 4 5 6 7 8 9 10 11 12 13
we need 17 single digit labels:
1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3
each label cost $1, so the output should be 17.