title: how can i plot a line on bar chart in R
body: <pre><code>H &lt;- c(1,2,4,1,0,0,3,1,3)
  M &lt;- c(&quot;one&quot;,&quot;two&quot;,&quot;three&quot;,&quot;four&quot;,&quot;five&quot;)
  barplot(H,names.arg=M,xlab=&quot;number&quot;,ylab=&quot;random&quot;,col=&quot;blue&quot;,
      main=&quot;bar chart&quot;,border=&quot;blue&quot;)
  </code></pre>
  <p>I want to add line on the bar chart , i don't know how to do it</p>
  <p>like the one in blue</p>
  <p><img src="https://i.stack.imgur.com/pN3Hg.png" alt="image" /></p>