N = int(input())
S = list(input().strip())
D = {"w","a","o","n","?"}
flag = True
for c in S:
    if c not in D:
        flag = False
        break
if flag:
    for i in range(N):
        if S[i]=="o":
            if i==0:
                flag = False
                break
            elif S[i-1]=="?":
                S[i-1] = "w"
            elif S[i-1]!="w":
                flag = False
                break
        elif S[i]=="a":
            if i==0:
                flag = False
                break
            elif S[i-1]=="?":
                S[i-1] = "w"
            elif S[i-1]!="w":
                flag = False
                break
    if flag:
        for i in range(N):
            if S[i]=="w":
                if i==N-1:
                    flag = False
                    break
                elif S[i+1]=="?":
                    S[i+1] = "a"
                elif S[i+1]!="a" and S[i+1]!="o":
                    flag = False
                    break
if flag:
    print("YES")
else:
    print("NO")