Let $S = \{ 1,2,3,4,5,6 \}$ and $X$ be the set of all relations $R$ from $S$ to $S$ that satisfy both the following properties:\\
i. $R$ has exactly 6 elements.\\
ii. For each $( a , b ) \in R$, we have $| a - b | \geq 2$.\\
Let $Y = \{ R \in X$ : The range of $R$ has exactly one element $\}$ and $Z = \{ R \in X : R$ is a function from $S$ to $S \}$.\\
Let $n ( A )$ denote the number of elements in a set $A$.\\
If the value of $n ( Y ) + n ( Z )$ is $k ^ { 2 }$, then $| k |$ is $\_\_\_\_$ .