Ositus

string = input()
mod = int(1e9+7)
ans = (1 << (len(string)-1)) - 1 % mod

for ch in string:
    if string.count(ch) > 1:
        count = string.count(ch)
        if count > 1:
            x1 = string.find(ch)
            x2 = string.find(ch, x1)
        while True:
            ans = (ans - (1 << (x1-x2+len(string)-1))) % mod
            count -= 1
            if count > 1:
                x1 = x2
                x2 = string.find(ch, x2)

print(ans)

Test 1

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 2

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 3

Group: 1, 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 4

Group: 1, 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 5

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 6

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 7

Group: 3

Verdict: TIME LIMIT EXCEEDED