Hot 100 March Madness 2013: Vote Now in Round 1!

From April 1, 2012 through the most recent charts on March 9, 2013, there have been exactly 32 songs that appeared in the Top 5 of the Hot 100 chart. The match-ups within the bracket were decided arbitrarily, so don't worry about NCAA-style rankings -- any song has a great chance of following "Hold It Against Me" and tasting Hot 100 March Madness glory.

Speaking of Britney Spears, the pop superstar and Will.i.am face a tough Round 1 opponent, as their hit "Scream & Shout" is matched up against One Direction's "What Makes You Beautiful." Other enticing Round 1 battles include Bruno Mars' "Locked Out of Heaven" facing off against Kelly Clarkson's "Stronger (What Doesn't Kill You)"; Nicki Minaj's ubiquitous 2012 hit "Starships" pitted against the recent viral smash (and No. 1 single) "Harlem Shake" by Baauer; PSY trying to topple Katy Perry's "Wide Awake" with "Gangnam Style"; and P!nk's attempt to blow one last kiss to Macklemore & Ryan Lewis, of "Thrift Shop" fame. Some artists, like Justin Bieber, Flo Rida, fun. and Rihanna, have more than one song in play, further increasing their chances of taking home a tournament win!

On Monday (March 11), we'll reveal the 16 songs that won their match-ups and survived the round of 32, and another round of voting will begin. On Thursday, March 28, a new Hot 100 March Madness champion -- the Top 5 song that you think was the No. 1 single of the past year -- will be crowned. Will Britney repeat as champ? Can Carly Rae Jepsen repeat her "Call Me Maybe" magic? And which Justin -- Bieber or Timberlake -- will advance further? It's up to you to decide!

Round 1 of Hot 100 March Madness is now CLOSED! See who moved on and get ready to vote in round 2, launching on Billboard.com Monday afternoon (March 11).