#include <iostream>
using namespace std;
int non(int n)
{
    int x = n, sum = 0;
    while (x > 0)
    {
        if (x % 10 == 1)
        {
            sum++;
        }
        x /= 10;
    }
    return sum;
}
int main()
{
    int n, sum = 0;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        sum += non(i);
    }
    cout << sum;
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,ans=0;
    cin>>n;
    for (int i=1;i<=n;i++)
    {
        if (i/1000==1)
            ans++;
        if (i/100%10==1)
            ans++;
        if (i/10%10==1)
            ans++;
        if (i%10==1)
            ans++;
    }
    cout<<ans;
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int n,sum;
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        int m=i;
        while(m>0)
        {
            if(m%10==1)
            {
                sum++;
            }
            m/=10;
        }
    }
    cout<<sum;
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n, s = 0; //s用作记录总共参加测试的次数
	cin >> n;
	//遍历1 ~ n号同学
	for(int i = 1; i <= n; i++){
		int num = 0, t = i;//num记录i号同学参加测试的次数
		//循环记录出i中有几个1
		while(t > 0){
			if(t % 10 == 1){
				num++;
			}
			t /= 10;
		} 
		//添加到总次数中
		s += num; 
	} 
	cout << s << endl;
	return 0;
}