def isAlt(a):
    if len(a)<=1:
        return False
    for i in range(1, len(a)+1):
        if a[i]*a[i-1] > 0:
            return False
        return True
    

def isGrow(a):
    if len(a)<=1:
        return False
    for i in range(1, len(a)+1):
        if a[i] < a[i-1]:
            return False
        return True

def isMulti(a):
    q = a[1]/a[0]
    if len(a)<=1:
        return False
    for i in range(2, len(a)):
        if a[i] / a[i-1] != q:
            return False
    return True

def isAdd(a):
    q = a[1]-a[0]
    if len(a)<=1:
        return False
    for i in range(2, len(a)):
        if a[i] - a[i-1] != q:
            return False
    return True