def query(T):
    T = "".join(T)
    print("? {}".format(T))
    return int(input())

N = int(input())
L = ["z"] * N
ans = ["! "]
for i in range(N):
    D = [0] * 25
    for j in range(25):
        L[i] = chr(j + ord("a"))
        D[j] = query(L)
    ma = max(D)
    if D.count(ma) == 1:
        ans.append(chr(ord("a") + D.index(ma)))
    else:
        ans.append("z")
    L[i] = "z"

print(*ans, sep="")