ch="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
odd,even=[],[]
for i in range(26):
    if i%2==0:
        even.append(ch[i])
    else:
        odd.append(ch[i])
l=[]
for i in range(26):
    for j in range(13):
        l.append(even[j])
        l.append(odd[(j+i)%13])
l.append("A")
ans=[]
for i in range(len(l)-1):
    ans.append(l[i]+l[i+1])
for a in ans:
    print(a)