#65 - 90
t=int(input())
B=[127,131,137,139,149]
for i in range(t):
n=int(input())
A=list(map(int,input().split()))
f=1
ans=0
tmp=0
for z in B:
f=1
for x in range(n):
if A[x]%z>=65 and A[x]%z<=90:
if x==n-1:
f=0
ans=z
tmp+=1
continue
else:
break
if ans==0 or tmp>1:
print("NIECZYTELNE")
continue
s=''
for x in range(n):
# print(A[x],ans)
integer=A[x]%ans
s+=chr(integer)
# print(s,z)
print(z,s)
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