I can't remember the name to a song with a piano intro?

I heard a song I THINK on the radio the other day, but I'm not
positive that's where. I believe it started out with a piano intro,
and I think it went into a girl singing, and then a guy? And then both
together (duet) for the rest of the song? But he beginning of the song
was about 55-70 BPM (beats per minute, as on a metronome) and the
counting would be "One, two, three, four ta te, one" or "One, two,
three, four e and, one" And it just repeated. The beginning measure of
notes could have been "C, C, C, C D Eb, Ab" (or transposed into
another key. Also, I'm not positive about the Ab at the end, but I'm
pretty sure it went lower). I just can't figure out what this song is,
and it is driving me craaaaaazy! I either heard it on the radio the
other day or on So You Think You Can Dance, but either way I'm pretty
sure it is a recent song. Please help! Thanks :)