My given string is "Today_is_Monday". If I apply Huffman's coding algorithm to this string. Without encoding, the total size of the string was (15*8) = 120 bits. After encoding the size is (10*8 + 15 + 49) = 144 bits.

As I know Huffman's algorithm uses to reduce size. But why the encoded size is more than its original?

More details I have done are given below

Thank you.