# there's some looseness here to account for people's mangling # of the English language entire_input ::= numbers 'End_Of_Input' numbers ::= [ NEGATIVE ] millions | thousands | hundreds | tens | teens | ones [ 'POINT' teens | ones { ones } ] millions ::= [ hundreds | teens | tens | ones ] 'MILLION' [ thousands | hundreds | teens | tens | ones ] thousands ::= [ hundreds | teens | tens | ones ] 'THOUSAND' [ hundreds | teens | tens | ones ] hundreds ::= [ teens | tens | ones ] 'HUNDRED' [ teens | tens | ones ] tens ::= twenty | thirty | forty | fifty | sixty | seventy | eighty | ninety teens ::= ten | eleven | twelve | thirteen | fourteen | fifteen | sixteen | seventeen | eighteen | nineteen ones ::= zero | one | two | three | four | five | six | seven | eight | nine