#flush=True
N=int(input())
D=dict()
alp="abcdefghijklmnopqrstuvwxyz"
skip=set()
ans=["." for i in range(N)]

print("?","a"*N,flush=True)
cnt_a=int(input())
print("?","b"*N,flush=True)
cnt_b=int(input())


for i in range(26):
	for j in range(N):
		if j in skip:
			continue
		if i==0:
		    L=["b" for k in range(N)]
		else:
		    L=["a" for k in range(N)]			
		L[j]=alp[i]
		print("?","".join(L),flush=True)
		n=int(input())
		if (i==0 and n==cnt_b) or (j>0 and n==cnt_a):
			ans[j]=alp[i]
			skip.add(j)

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