Osajono

#include <cstdio>
#include <iostream>
#include <vector>

using namespace std;

#define REP(n) for(__typeof(n) _i=0; _i<(n); ++_i)
#define FOR(i,a,b) for(__typeof(b) i=a; i<b; ++i)
#define FORE(i,a,b) for(__typeof(b) i=a; i<=b; ++i)
#define S(x) scanf("%d", &(x))

typedef long long LL;

#define MAX(a,b) ((a)<(b) ? (b) : (a))

int main() {
    LL a[255], ways = 0;

    for(int c='A'; c<='Z'; c++) a[c] = 0;

    while(1) {
        int ch = getc(stdin);
        if(ch < 'A' || ch > 'Z') break;
        a[ch]++;
    }

    for(int c='A'; c<='Z'; c++)
        if(a[c])
            ways += a[c]*(a[c]-1)/2 + a[c];

    cout << ways << endl;

    return 0;
}

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