Given a list of web nagivation tasks, your task is to extract the common workflows to solve these tasks.
Each given task contains a natural language instruction, and a series of actions to solve the task. You need to find the repetitive subset of actions across multiple tasks, and extract each of them out as a workflow.
Each workflow should be a commonly-reused sub-routine of the tasks. Do not generate similar or overlapping workflows. Each workflow should have at least two steps.