def vect_prod_s(_V1, _V2):
    """
    Returns scalar product of vectors V1 and V2
    """
    sizeV1 = len(_V1)
    sizeV2 = len(_V2)
    sizeV = sizeV1 if(sizeV1 < sizeV2) else sizeV2
    res = 0
    for i in range(sizeV): res += _V1[i]*_V2[i]
    return res