# BNF ```bnf -> program ; -> [][][] -> const {, } ; -> :=

-> var {, } ; -> procedure ([ {, }]) ; {; } -> begin {; } end -> := | if then [else ] | while do | call ([ {, }]) | | read ( {, }) | write ( {, }) -> | odd -> [+|-] { } -> { } -> | | () -> = | <> | < | <= | > | >= -> + | - -> * | / -> { | } -> {} -> a | b | ... | z | A | B | ... | Z -> 0 | 1 | ... | 9 ```