The square root is a positive integer within 200! This problem is to investigate the parity of each factor of 1~200. The lamp state with odd factor is different from the initial state. On the contrary, the lamp state remains unchanged when the factor is even. Give two examples: No.2 light has two factors (2 = 1 and 2), so it is switched on and off twice, and the state remains unchanged; There are three factors in the No.4 light: 1, 2, 4, (4= 14=22) press it three times, which is different from the initial state, that is, the light is off at first, and it will light up after pressing it three times.

1。 4。 9. 16.25.36.49.64.8 1. 100。 12 1。 144. 169.438+096 opened.