[1u] r-t 1 r - [1e]-r t 1 r - 1--1-- 1--1-- [1e] r-t 1 r - [1e]-r t 1-- 1--1-- 1--1 - 0 [1e]-r t 1 r - [1e]-r t 1 r - 1--1-- 1--1-- [1e]-r t 1-r- [1e]-r t 1-- [$I]--2-- 2--2-- 2--[2y]-- [2y]y--[2u] y t yt [1u]--1-- 1--[5u]-[$I]- [3u]-t t [1t] t t t [:t'y]-r r [:t'r] e-w [1u]--1-- 1--1-- [3u]-t t [1t] t t t [:t'y]-r r [:t'r] e-w [1u]--1-- 1--1