Five different games are to be distributed among four children randomly. The probability that each child get at least one game is $p,$ then the value of $\left[\frac{1}{p}\right]$ is_, where $\left[·\right]$ represents the greatest integer function.

Four numbers are chosen at random (without replacement) from the set $\left\{1, 2, 3,...,20\right\}.$

Statement $1$ :

The probability that the chosen numbers when arranged in some order will form an $A.P.$ is $\frac{1}{85}.$

Statement $2$ :

If the four chosen numbers form an $A.P.,$ then the set of all possible values of common difference is $\left\{\pm 1, \pm 2, \pm 3, \pm 4, \pm 5\right\}.$

For three events$A, B$ and $C,$ if$P$ (exactly one of $A$ or $B$ occurs) $=P$ (exactly one of $B$ or $C$ occurs) $=P$ (exactly one of $C$ or $A$ occurs) $=\frac{1}{4}$ and $P$ (all the three events occur simultaneously) $=\frac{1}{16},$ then the probability that atleast one of the events occurs, is