from math import pi, asin, cos, sin, sqrt

def spherical_distance(a, b):
    coef = pi / 180
    radlat1 = a[1] * coef
    radlat2 = b[1] * coef
    radlng1 = a[0] * coef
    radlng2 = b[0] * coef
    a = sin((radlat1 - radlat2)/2)**2
    b = cos(radlat1) * cos(radlat2) * sin((radlng1 - radlng2)/2) ** 2
    return asin(sqrt(a+b))

def ang_distance(a, b):
    x = abs(a-b)
    return min(x, 360-x)