1. A memory system, comprising: a non-volatile memory device including a normal region in which Most Significant Bits (MSBs) and Least Significant Bits (LSBs) stored in memory cells are simultaneously accessed, a hot region in which MSBs stored in memory cells are accessed, and a cold region in which LSBs stored in memory cells are accessed; and a memory controller suitable for controlling the non-volatile memory device, wherein the memory controller includes: a read/write counter suitable for counting the number of times that a read operation is performed and the number of times that a write operation is performed for each of a plurality of logical clusters to thereby produce a counting result; and a region selector suitable for mapping each of the logical clusters o one region among the normal region, the hot region and the cold region based on the counting result to thereby produce mapping data.