Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Skin Cancer ?
    ### Response:
    Skin cancer is the most common type of cancer in the U.S. It occurs in more than a million people each year, including many older people. There are three main types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma. Of the three, melanoma is the most serious.
    