panic: ref solver crashed: exit status 2
panic: runtime error: index out of range [-1]

goroutine 1 [running]:
main.main()
	/tmp/cf-worker-3482765507/1423A.go:160 +0xf14


goroutine 1 [running]:
main.refSolve({0x40000a8000, 0x78})
	/tmp/cf-worker-3482765507/verifierA.go:57 +0x248
main.main()
	/tmp/cf-worker-3482765507/verifierA.go:118 +0x2bc