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.
#include <iostream>
using namespace std;

int main() {
	int n;
	cin >> n;

	int d = 1;
	long long int dd = 10;
	long long ans = 0;
	int h = 1;
	while(dd < n) ans += (dd - d + 1) * h, h++, d = dd, dd *= 10;
	ans += (n - d) * h;
	cout << ans + 1 << endl;
	return 0;
}