I guess you're referring to Feb 18th 1913, when Pedro Lascur�in became the world's briefest president, lasting a whopping 45 minutes, so the answer would be Mexico had 3 presidents in the space of 24 hours ........
Francisco I. Madero
succeeded by Pedro Lascur�in
succeeded by Victoriano Huerta
...... all within 24 hours ..... well, 45 minutes actually - but there you go :P