14468번 소가 길을 건너간 이유2

14468번: 소가 길을 건너간 이유 2 (acmicpc.net)

from sys import stdin

STR = stdin.readline().strip("\n")

A_ASCII = 65
B_ASCII = 90

CAW = {}

for i in range(A_ASCII, B_ASCII + 1):
    CAW[chr(i)] = {
        "start": "",
        "end": "",
    }

for i, value in enumerate(STR):
    if CAW[value]["start"] == "":
        CAW[value]["start"] = i
    else:
        CAW[value]["end"] = i

ANSWER = 0

for FROM, FROM_TIME in CAW.items():
    for DEST, DEST_TIME in CAW.items():
        if FROM == DEST:
            continue

        FROM_START = FROM_TIME["start"]
        FROM_END = FROM_TIME["end"]

        DEST_START = DEST_TIME["start"]
        DEST_END = DEST_TIME["end"]

        if FROM_START <= DEST_START and FROM_END <= DEST_END and DEST_START <= FROM_END:
            ANSWER += 1

print(ANSWER)