import collections,sys,math,functools,operator,itertools,bisect,heapq,decimal,string,time,random
sys.setrecursionlimit(10**9)
#sys.set_int_max_str_digits(0)
n = int(input())
print('?','z'*n,flush=True)
z = int(input())
if z == n:
    print('!','z'*n,flush=True)
    exit()
ans = ['' for i in range(n)]

for i in range(n):
    temp = ['z' for i in range(n)]
    for j in range(25):
        temp[i] = chr(j + ord('a'))
        print('?',''.join(temp),flush=True)
        x = int(input())
        if x == z-1:
            ans[i] = 'z'
            break
        if x == z +1:
            ans[i] = temp[i]
            break
print('!',''.join(ans))