print(99)
print(1, 2)
print(2, 3)
print(3, 4)
print(4, 5)
print(5, 6)
print(6, 7)
print(7, 8)
print(8, 9)
print(9, 10)
print(10, 11)
print(11, 12)
print(12, 13)
print(13, 14)
print(14, 15)
print(15, 16)
print(16, 17)
print(17, 18)
print(18, 19)
print(19, 20)
print(20, 21)
print(21, 22)
print(22, 23)
print(23, 24)
print(24, 25)
print(25, 26)
print(26, 27)
print(27, 28)
print(28, 29)
print(29, 30)
print(30, 31)
print(31, 32)
print(32, 33)
print(33, 34)
print(34, 35)
print(35, 36)
print(36, 37)
print(37, 38)
print(38, 39)
print(39, 40)
print(40, 41)
print(41, 42)
print(42, 43)
print(43, 44)
print(44, 45)
print(45, 46)
print(46, 47)
print(47, 48)
print(48, 49)
print(49, 50)
print(50, 51)
print(51, 52)
print(52, 53)
print(53, 54)
print(54, 55)
print(55, 56)
print(56, 57)
print(57, 58)
print(58, 59)
print(59, 60)
print(60, 61)
print(61, 62)
print(62, 63)
print(63, 64)
print(64, 65)
print(65, 66)
print(66, 67)
print(67, 68)
print(68, 69)
print(69, 70)
print(70, 71)
print(71, 72)
print(72, 73)
print(73, 74)
print(74, 75)
print(75, 76)
print(76, 77)
print(77, 78)
print(78, 79)
print(79, 80)
print(80, 81)
print(81, 82)
print(82, 83)
print(83, 84)
print(84, 85)
print(85, 86)
print(86, 87)
print(87, 88)
print(88, 89)
print(89, 90)
print(90, 91)
print(91, 92)
print(92, 93)
print(93, 94)
print(94, 95)
print(95, 96)
print(96, 97)
print(97, 98)
print(98, 99)
print(99, 100)