import java.io.*;
class Input{
	public static final double log10(double y) {
	 double logbeten = Math.log(10);
	 double logbey = Math.log(y);
	 double w = logbey / logbeten;
	 return w;
	}


	public static void main(String[] args) throws IOException {						BufferedReader stdin = 
	        new BufferedReader ( new InputStreamReader( System.in ) );
		String bob;
		System.out.println("Enter first integer:");
		int llama;
		bob = stdin.readLine();
		llama = Integer.parseInt(bob);
		System.out.println(log10(llama));
	}
}