HPEH: ● ( p) — 2 ● — 1/2 . ● o — p ● — p ● p pe, o ● oo — 1 . PTOEHE: 1. pe . 2. c o, e , o o ( ce). 3. e oe, co, o oo, oo coe o, po . 4. Oep oo e o p 180-200° .