panic: invalid argument to Intn goroutine 1 [running]: math/rand.(*Rand).Intn(0x0?, 0xe?) /usr/local/go/src/math/rand/rand.go:180 +0x64 main.genTest(0x400006ce90) /home/ubuntu/codeforces/1000-1999/1300-1399/1380-1389/1389/verifierG.go:147 +0x60 main.main() /home/ubuntu/codeforces/1000-1999/1300-1399/1380-1389/1389/verifierG.go:222 +0x180 exit status 2