def SEIR_Map(state):
    """
    Encodes the literal SEIR state to an integer.

    Args:
        (str): State of the human i.e. S, E, I, or R
    """
    if state == "S":
        return 0
    if state == "E":
        return 1
    if state == "I":
        return 2
    if state == "R":
        return 3