English Number Translator

In this problem you are given one or more integers written out in English. Your task is to translate each number into its integer representation. The numbers range from -999,999,999 to 999,999,999. The following is the exhaustive list of English words your program must account for.

negative, zero, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety, hundred, thousand, million

The input consists of several instances, one per line. Notes on the input:

1. Negative numbers are preceded by the word negative.
2. The word hundred is not used when thousand could be used instead. For example, 1500 is written as one thousand five hundred, not fifteen hundred.

The input is terminated by an empty line.

For each instance, print its integer value on its own line, with a newline after each answer.