title: Building regex to match 2 words only
body: <p>I'm trying to make regexp that match only 2 words and a single pace between. No special symbols, only <code>[a-zA-Z]</code> space <code>[a-zA-z]</code>.</p>
  
  <pre><code>Foo Bar      # Match    (two words and one space only)
  Foo          # Mismatch (only one word)
  Foo  Bar     # Mismatch (2 spaces)
  Foo Bar Baz  # Mismatch (3 words)
  </code></pre>