EnableExplicit

Procedure.F ProbA(Ga.L, WiA.L, WiB.L)
    If WiA = 4
        ProcedureReturn 1
    EndIf
    If WiB = 4
        ProcedureReturn 0
    EndIf
    Protected.F PrA, PrB, PrH
    Ga + 1
    PrH = 0.51
    If Ga <= 3
        PrA = PrH
    Else
        PrA = 1 - PrH
    EndIf
    PrB = 1 - PrA
    ProcedureReturn PrA*ProbA(Ga, WiA + 1, WiB) + PrB*ProbA(Ga, WiA, WiB + 1)
EndProcedure

Debug StrF(ProbA(0, 0, 0), 7)