#include <bits/stdc++.h>
#define ll long long
using namespace std;
bool q;
long long qwe(long long x)
{
	long long m = x , l = 0;
	while (m != 0)
	{
		l += m % 10;
		m /= 10;
	}
	return l;
}
	
int main()
{
	ll a , b = 0 , o;
	cin >> a;
	o = 0;
	if (a >= 100000000ll)
	{
		for (ll i = 1; i <= a / 100000000; i++)
		{
			b += 3600000001ll + 100000000ll * o;
			o++;
		}
		a %= 100000000ll;
	}
	o = 0;
	if (a >= 10000000)
	{
		for (ll i = 1; i <= a / 10000000; i++)
		{
			b += 315000001ll + 10000000 * o;
			o++;
		}
		a %= 10000000;
	}
	o = 0;
	if (a >= 1000000)
	{
		for (ll i = 1; i <= a / 1000000; i++)
		{
			b += 27000001 + 1000000 * o;
			o++;
		}
		a %= 1000000;
	}
	o = 0;
	if (a >= 100000)
	{
		for (ll i = 1; i <= a / 100000; i++)
		{
			b += 2250001 + 100000 * o;
			o++;
		}
		a %= 100000;
	}
	o = 0;
	for (ll i = 1; i <= a; i++)
	{
		b += qwe(i);
	}
	cout << b;
	return 0;
}