Add Share This Button To WordPress

I try to avoid loading to many plugins to our WordPress blog, I prefer to add the Share This button manually to our single post (single.php). Add the script to the header.php just before </head> <script type=”text/javascript” src=”//w.sharethis.com/button/buttons.js”></script> Now, add this codes to wherever I want to appear in the single.php. Remove the ‘ both