_if = "если"
_then = "значит"
_before = "перед"
_after = "после"

words = [_if,_then,_before,_after]

def phrase(a,b) :
    orders = ( [a,_before,b], [b,_after,a] )
    return ( ' '.join([_if]+x+[_then]+y) for x in orders for y in orders )

phrases = sorted(p for a in words for b in words for p in phrase(a,b))

for i,p in enumerate(phrases,1) :
    print "%d) %s." % (i,p)

#-*- coding: utf-8 -*-

_if = "если"
_then = "значит"
_before = "перед"
_after = "после"
_not = "не"

words = [_if,_then,_before,_after,_not]

def viceversa(a,b) :
    return [ (a,b), (b,a) ]

def template(x,y) :
    return ' '.join([_if] + x + [_then] + y)

def phrase(a,b) :
    # шаблоны выражений:
    lt = [ [a,_before,b], [_before,b,a] ]
    gt = [ [b,_after,a], [_after,a,b] ]
    le = [ [a,_not,_before,b] ]
    ge = [ [b,_not,_after,a] ]
    # придумайте и другие пары отношений...
    pairs = [ (lt,gt), (le,ge) ]
    for p,q in pairs : # выбираем зеркальные отношения
        for p1,q1 in viceversa(p,q) : # отработаем их в обе стороны
            for x in p1 :
                for y in q1 :
                    yield template(x,y)

phrases = sorted(set(p for a in words for b in words for p in phrase(a,b)))

print len(phrases)
for i,p in enumerate(phrases,1) :
    print "%d) %s." % (i,p)