N=int(input())
alp=[chr(i) for i in range(97,97+26)]
S=[]
for i in range(N):
    T=["a"]*N
    C=[]
    for a in alp[:25]:
        T[i]=a
        print("?")
        print(*T,sep="")
        C.append(int(input()))
    ma=max(C)
    if C.count(ma)==1:
        S.append(alp[C.index(ma)])
    else:
        S.append(alp[25])
print("!")
print(*S,sep="")