title: Sum up numbers after string "number"
body: <p>I have a text file with words and positive numbers, separated by some whitespace, e.g.</p>
  
  <pre><code>A dog has a ball number 49     number    34 number    A
  Cats number   58
  ...
  </code></pre>
  
  <p>I want to sum up all the numbers that occur after the string "number". If after a string "number" is not a number, then it doesn't matter.</p>
  
  <p>For example, in this case the answer would be 49+34+58, which is <code>141</code>.</p>