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

goroutine 1 [running]:
main.main()
	/tmp/cf-worker-3048039607/1423A.go:160 +0xf14


goroutine 1 [running]:
main.refSolve({0x4000254080, 0x74})
	/tmp/cf-worker-3048039607/verifierA.go:57 +0x248
main.main()
	/tmp/cf-worker-3048039607/verifierA.go:118 +0x2bc