quick math question how often should i call with my bluff catchers ?

For the sake of clarification i'm not talking about pot odds. I want to know what my calling frequency should be in order to become indifferent to whether he is bluffing or value betting. Actually that isn't exactly right as being indifferent would mean it doesn't matter how often he is betting/bluffing. so i want to know how often i need to call to his strategy of value betting 60 percent and bluffing 40 percent 0ev or as close to 0 ev as possible.