A succession of hits followed quickly , including `` Hey Little Girl '' , `` Um , Um , Um , Um , Um , Um '' ( his biggest hit , reaching # 5 in the US pop chart and # 40 in the UK , where it was his only chart success ) , `` The Matador '' ( the only one not written by Mayfield ) , `` Rhythm '' , `` Sometimes I Wonder '' , `` Come See '' , and `` Ai n't It A Shame '' .
His hits quickly became more successful , including `` Hey Little Girl '' , `` Um , Um , Um , Um , Um , Um '' ( his biggest hit , reaching # 5 in the US pop chart and # 40 in the UK , where it was his only chart success .