city #0
city #3
city #6
city #9
city #12
city #15
city #18
city #21
city #24
city #27
city #30
city #33
city #36
city #1
city #4
city #7
city #10
city #13
city #16
city #19
city #22
city #25
city #28
city #31
city #34
city #2
city #5
city #8
city #11
city #14
city #17
city #20
city #23
city #26
city #29
city #32
city #35