>in</span> <span class="hljs-number">0</span> ..&lt; l:
    d.addLast(s[i])
    p.incl s[i]
  <span class="hljs-keyword">block</span> findInvalid:
    <span class="hljs-keyword">for</span> i <span class="hljs-keyword">in</span> l ..&lt; s.len:
      n = s[i]
      <span class="hljs-keyword">block</span> findPair:
        <span class="hljs-keyword">for</span> m <span class="hljs-keyword">in</span> d:
          <span class="hljs-keyword">if</span> n != m <span class="hljs-keyword">and</span> n - m <span class