1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 7
8. 8
9. 9
10. 10
11. 11
12. 12
13. 13
14. 14
15. 15
16. 16
17. 17
18. 18
19. 19
20. 20
21. 21
22. 22
23. 23
24. 24
25. 25
26. 26
27. 27
28. 28
29. 29
30. 30
31. 31
32. 32
33. 33
34. 34
35. 35
36. 36
37. 37
38. 38
39. 39
40. 40
41. 41
42. 42
43. 43
44. 44
45. 45
46. 46
47. 47
48. 48
49. 49
50. 50
51. 51
52. 52
53. 53
54. 54
55. 55
56. 56
57. 57
58. 58
59. 59
60. 60
61. 61
62. 62
63. 63
64. 64
65. 65
66. 66
67. 67
68. 68
69. 69
70. 70
71. 71
72. 72
73. 73
74. 74
75. 75
76. 76
77. 77
78. 78
79. 79
80. 80
81. 81
82. 82
83. 83
84. 84
85. 85
86. 86
87. 87
88. 88
89. 89
90. 90
91. 91
92. 92
93. 93
94. 94
95. 95
96. 96
97. 97
98. 98
99. 99

print('1 часть тут, 2 в описании')
import re
q = int(input())
b = input()
v = 0
flag = True
if v == 0:
    c = len(re.findall('q', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('w', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('e', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('r', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('t', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('y', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('u', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('i', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('o', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('p', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('a', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('s', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('d', b))
    if c > 1:
        print("NO")
        flag = False
        quit()
    else:
        v = 3
    c = len(re.findall('f', b))