a(b,c) 1 a(b,c) eq okay teq okay a(b,c) b c 1(2,3(4,5,6(7))) 3 1(2,3(4,5,6(7))) eq okay teq okay 1(2,3(4,5,6(7))) 2 3(4,5,6(7)) 4 5 6(7) 7 1(2(3(4(5(6(7)))))) 6 1(2(3(4(5(6(7)))))) eq okay teq okay 1(2(3(4(5(6(7)))))) 2(3(4(5(6(7))))) 3(4(5(6(7)))) 4(5(6(7))) 5(6(7)) 6(7) 7