#flush=True
N=int(input())
D=dict()
alp="abcdefghijklmnopqrstuvwxyz"
skip=set()
ans=["." for i in range(N)]
for i in range(26):
	for j in range(N):
		if j in skip:
			continue
		L=["." for k in range(N)]
		L[j]=alp[i]
		print("?","".join(L))
		n_raw=input()
		n=int(n_raw)
		if n==1:
			ans[j]=alp[i]
			skip.add(j)

print("!","".join(ans),flush=True)