import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(Sysyem.in);
        String s = sc.nextLine();
        
        boolean isDigitOnly = true;
        for (int i =0; i<s.length(); i++) {
            if (!Character.isDigit(s.charAt(i))) {
                isDigitOnly = false;
                break;
            }
        }
        System.out.println(isDigiOnly ? "true" : "false")
    }
}