SQL Server 2012 license

I have a few questions about licensing the volume of SQL Server for my company. Our server system is configured with Failover Cluster ( 2 note). These include 2 servers with SQL Server Standard 2012 installed, and only 1 of them working at a time (Active\Passive). Our entire database is stored on SAN Storage devices.
So the number of licenses my company has to buy for 2 servers that install SQL Server is 2 or just 1. Thanks!