Show Brazil Singers Plan Endurance Concerts S SAO O PAULO P A ULO Brazil Dec 22 AP Singing marathons have replaced endurance dancing dancing- as the popular fad of ot loving novelty Sao Sno Paulo Paulista has challenged Mario Pinheiro to a singing contest I which it is estimated will wili last fifteen 11 if- if teen hours The rules rule say that I b both th must sing the same music tale take two minutes' minutes rest each hour change chango their tune every ten ten minutes and agree not to use strengthening drugs u |