N = int(input()) S = input() i = 0 while i<N: if i+1<N and S[i]=="w" and (S[i+1]=="a" or S[i+1]=="o" or S[i+1]=="?"): i+=2 elif S[i]=="n": i+=1 elif i+1<N and S[i]=="?" and (S[i+1]=="a" or S[i+1]=="o"): i+=2 elif S[i]=="?": i+=1 else: print("No") exit() print("Yes")