panic: invalid argument to Intn

goroutine 1 [running]:
math/rand.(*Rand).Intn(0x40000c0000?, 0x7d42c?)
	/usr/local/go/src/math/rand/rand.go:180 +0x64
main.generateCases(0x40000a0ed0)
	/home/ubuntu/codeforces/0-999/300-399/340-349/343/verifierE.go:173 +0x90
main.main()
	/home/ubuntu/codeforces/0-999/300-399/340-349/343/verifierE.go:214 +0x168
exit status 2