  The packing of three copies of a graph $G$ is the union of three
edge-disjoint copies (with the same vertex set) of $G$. In this paper, we
completely solve the problem of the uniqueness of packing of three copies of
2-regular graphs. In particular, we show that $C_3,C_4,C_5,C_6$ and $2C_3$ have
no packing of three copies, $C_7,C_8,C_3 \cup C_4, C_4 \cup C_4, C_3 \cup C_5$
and $3C_3$ have unique packing, and any other collection of cycles has at least
two distinct packings.
