JEE Main 1996 Mathematics question on Probability

For the three events $A$, $B$ and $C$, $P$(exactly one of the events $A$ or $B$ occurs) $= P$(exactly one of the events $B$ or $C$ occurs) $= P$(exactly one of the events $C$ or $A$ occurs) $= p$ and $P$(all the three events occurs simultaneously) $= p^2$, where $0 < p < \frac{1}{2}$. Then, the probability of atleast one of the three events $A$, $B$ and $C$ occurring is