Babaza Game

s = input()
t = input()

def is_valid(x):
    n = len(x)
    if n == 1:
        return True
    for i in range(1,n):
        if x[i] == x[i - 1]:
            return False
    return True

def is_ok(cur, bef, aft):
    if bef != None and cur == bef:
        return False

    if aft != None and cur == aft:
        return False

    return True

print(s)
n = len(s)

if n == 1:
    print(t)
    exit(0)

pos = []
ok = True

for i in range(n):
    if s[i] != t[i]:
        if len(pos) == 0:
            pos.append(i)
        elif abs(pos[-1] - i) <= 1:
            ok = False
            break

if ok:
    print(t)
    exit(0)

while s != t:
    c1 = list(s)
    for i in range(0, n, 2):
        if s[i] != t[i]:
            ok = True
            if 0 <= i - 1 and s[i - 1] == t[i]:
                ok = False
            if i + 1 < n and s[i + 1] == t[i]:
                ok = False

            if ok:
                c1[i] = t[i]

    c2 = list(s)
    for i in range(1, n, 2):
        if s[i] != t[i]:
            ok = True
            if 0 <= i - 1 and s[i - 1] == t[i]:
                ok = False
            if i + 1 < n and s[i + 1] == t[i]:
                ok = False

            if ok:
                c2[i] = t[i]

    dif1 = 0
    dif2 = 0

    for i in range(n):
        if c1[i] != t[i]:
            dif1 += 1
        if c2[i] != t[i]:
            dif2 += 1

    if dif1 < dif2:
        s = ''.join(c1)
        print(s)
        continue

    if dif1 > dif2:
        s = ''.join(c2)
        print(s)
        continue

    c3 = list(s)
    for i in range(0, n, 2):
        if s[i] != t[i]:
            ok = True
            if 0 <= i - 1 and s[i - 1] == t[i]:
                ok = False
            if i + 1 < n and s[i + 1] == t[i]:
                ok = False

            if ok:
                c3[i] = t[i]
            else:
                for kem in "ABCDEFGHIJKLMNOPQRSTUVWXYZ":
                    bef = None
                    aft = None
                    if 0 <= i - 1:
                        bef = s[i - 1]
                    if i + 1 < n:
                        aft = s[i + 1]
                    if is_ok(kem, bef, aft):
                        c3[i] = kem


    s = ''.join(c3)

    print(s)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED