Find the number of characters in a given number?

//ONLY USABLE TILL A 3 DIGIT NUMBER
import java.io.;
import java.util.;

public class Solution
{
static void Digits(int n)
{
int c=0;
for(int i=1;i<=n;i++)
{
if(i<=9)
c=c+1;
else if(i>=10&&i<=99)
c=c+2;
else
{
c=c+3;
}
}
System.out.print(c);
}
public static void main(String[] args)
{
Scanner s=new Scanner(System.in);
int a=s.nextInt();
Digits(a);
}
}