Ositus

from itertools import chain, combinations

maara = 0
sallittu = True

def permute(s):
	sallittu = True
	result = [[s]]
	for i in range(1, len(s)):
		first = [s[:i]]
		rest = s[i:]
        
		if len("".join(set((first[0])))) != len(first[0]):
			sallittu = False
			return (result)
		if len("".join(set((rest)))) != len(rest):
			sallittu = False
			return (result)
		for p in permute(rest):
			if len("".join(set((p[0])))) != len(p[0]):
				sallittu = False
				return (result)
				result.append(first + p)
	return (result)

s = input()
for i in permute(s):
	if (sallittu):
		maara += 1

print((maara-1)%(10**9+7))

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: WRONG ANSWER

Test 4

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 5

Group: 2, 3

Verdict: WRONG ANSWER

Test 6

Group: 3

Verdict: WRONG ANSWER

Test 7

Group: 3

Verdict: WRONG ANSWER