package Entropy;import java.util.Scanner;public class Entropy {    public static double Entropy(String str) {        double H = 0.0;        int sum = 0;        int[] letter = new int[26];        str = str.toUpperCase();        for (int i = 0; i < str.length(); i++) {            char c = str.charAt(i);            if (c >= 'A' && c <= 'Z') {                letter[c - 'A']++;                sum++;            }        }        for (int i = 0; i < 26; i++) {            double p = 1.0 * letter[i] / sum;            if (p > 0) {                H += (p * Math.log(p) / Math.log(2));            }        }        return H;    }    public static void main(String[] args) {      Scanner scanner=new Scanner(System.in);   String string= scanner.next();double H=Entropy(string);System.out.println(H);    }}