TASK DEFINITION: In this task you will be given a string that only contains single digit numbers spelled out. The input string will not contain spaces between the different numbers. Your task is to return the number that the string spells out. The string will spell out each digit of the number for example '1726' will be 'oneseventwosix' instead of 'one thousand seven hundred six'.
PROBLEM: twofivethreeonesixfive

SOLUTION: 253165

PROBLEM: onefourfivethreethreezerothree

SOLUTION: 1453303

PROBLEM: eightonefivefourtwofivefiveoneeightzeroninesix

SOLUTION:
815425518096