import math

def du(x1, y1, x2, y2):

    angle = 0.0
    dx = x2 - x1
    dy = y2 - y1
    if x2 == x1:
        angle = math.pi / 2.0
        if y2 == y1:
            angle = 0.0
        elif y2 < y1:
            angle = 3.0 * math.pi / 2.0
    elif x2 > x1 and y2 > y1:
        angle = math.atan(dy / dx)
    elif x2 > x1 and y2 < y1:
        angle =2* math.pi- math.atan(-dy / dx)
    elif x2 < x1 and y2 < y1:
        angle = math.pi + math.atan(dy / dx)
    elif x2 < x1 and y2 > y1:
        angle = math.pi / 2.0 + math.atan(-dx / dy)
    elif y2 == y1 and x2<x1:
        angle = math.pi
    elif y2 == y1 and x2>x1:
        angle = 0.0
    return (angle * 180 / math.pi)

d=du(10,10,1,-1)
print(d)