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: zerozerothreezeroninefivefive

SOLUTION: 0030955

PROBLEM: zerosixeightonenineninezero

SOLUTION: 0681990

PROBLEM: sixeighteightzeronine

SOLUTION:
68809