"""

先頭だけ続く文字に置き換え、それ以外は
全部aに置き換える誤解法

"""

S = input()

ANS = []

wait = 0

for i in S:
    if i == "?" and len(ANS) > 0:
        ANS.append("a")
    elif i == "?":
        wait += 1
    else:
        ANS.append(i*(wait+1))
        wait = 0

print ("".join(ANS))