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'.

sixzerothreethreeeighteight
603388

twoonetwothreesixnine
212369

threeonesixfivethreesevenseven

3165377