panic: invalid argument to Intn

goroutine 1 [running]:
math/rand.(*Rand).Intn(0x1c8490?, 0xe3e80?)
	/usr/local/go/src/math/rand/rand.go:180 +0x64
main.generateTests()
	/home/ubuntu/codeforces/1000-1999/1000-1099/1060-1069/1065/verifierE.go:44 +0x3f0
main.main()
	/home/ubuntu/codeforces/1000-1999/1000-1099/1060-1069/1065/verifierE.go:77 +0x1a8
exit status 2