The Lonely by Christina Perri is in Cm at 75 beats per minute and runs 3:22 across 52 bars. It uses 7 chords — Gm, D, Eb, Bb, D7, F, Cm. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? The Lonely guitar melody tab.