panic: invalid argument to Intn

goroutine 1 [running]:
math/rand.(*Rand).Intn(0x12a078?, 0x40000b0140?)
	/usr/local/go/src/math/rand/rand.go:180 +0x64
main.genCases()
	/home/ubuntu/codeforces/0-999/700-799/730-739/730/verifierK.go:54 +0x250
main.main()
	/home/ubuntu/codeforces/0-999/700-799/730-739/730/verifierK.go:109 +0x108
exit status 2