Osajono

import java.util.Scanner;


public class Main {

	public static void main(String[] args) {
		Scanner lukija = new Scanner(System.in);
		
		String jono = lukija.nextLine();
		
		int[] maarat = new int[26];
		
		long maara = 0;
		
		for (char c : jono.toCharArray()) {
			int i = (int)(c - 'A');
			maara += ++maarat[i];
		}
		
		System.out.println(maara);
		
		lukija.close();
	}

}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED