1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
def rep(s, t):
    if t == 0:
        return ''

    if t == 1:
        return s
    
    if t <= 9:
        return f'{t}[{s}]'

    return rep(rep(s, t // 9), 9) + rep(s, t % 9) 

def tri(n):
    if n == 1:
        return 'B'

    l = n // 2
    r = n - l

    out = tri(l)

    line = rep('D', l) + rep('BF', l - 1) + 'B'
    out += rep(line, r)
    out += rep('F', r)

    out += tri(r)
    return out

def tri2(n):
    assert n > 0
        
    if n == 1:
        return 'B'
    if n % 2 == 0:
        s = tri2(n - 1)
        line = rep('D', n - 1) + rep('BF', n - 1) + 'B'
        return s + line

    m = n // 2
    #assert m % 2 == 1
    
    rec = tri2(m)
    
    out = rep(rec, 2)
    out += rep('D', m)
    out += rep('F', m)
    out += rep('D', m)
    

    line = rep('BF', m - 1) + 'B' + rep('D', m)
    out += rep(line, m)
    out += rep('BF', m + m) + 'B'

    return out
    
        

n = int(input())
print(tri2(n) + rep('D', n) + rep('F', n))