Ositus

def noOverlaps(a,b):
    for i in range(len(a)):
        if b.find(a[i])!=-1:
            return False
    return True

U=input()
I=U[1:]
ends={U[0]:1}
for i in range(len(I)):
    s=I[i]
    newEnds={s:0}
    for k in ends.keys():
        if k.find(s)==-1:
            sortEnd=''.join(sorted(k+s))
            newEnds.setdefault(sortEnd,0)
            newEnds[sortEnd]+=ends[k]
        newEnds[s]+=ends[k]
    ends=newEnds
    #print(ends)

total=0
for k in ends.keys():
    total+=ends[k]
print(total%(7+(10**9)))

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 2, 3

Verdict: ACCEPTED

Test 6

Group: 3

Verdict: ACCEPTED

Test 7

Group: 3

Verdict: TIME LIMIT EXCEEDED