def add_is_prefix(input_string):
    # Check if the string already starts with "Is"
    if input_string.startswith("Is"):
        return input_string
    else:
        # Add "Is" to the front of the string
        return "Is" + input_string

# Example usage:
print(add_is_prefix("Island"))  # Output: Island
print(add_is_prefix("land"))    # Output: Island