OP_LESSTHAN compares the top two items on the stack and checks if the second-to-top item is less than the top item. If so, it pushes 1 (true) onto the stack; otherwise, it pushes 0 (false). This opcode is used in scripts that require a less-than comparison between numerical values.
OP_Code Walkthrough
Returns 0x01 if item-1 is less than item-2, 0x00 otherwise
Pop Top Item a
Pop Top Item b
Check if b is less than a
Push Result