YSITD_TG_Bot says to #ysitd <koru1130>: /js@mmis_js_bot let Y = f => (x => f( (y) => (x(x))(y) ))(x => f((y) => (x(x))(y))) let fac = f => x =>( (x<=1)? 1 : x*f(x-1)) console.log(Y(fac)(3))