import sys

from math import atan, pi



read = sys.stdin.read

readline = sys.stdin.readline

readlines = sys.stdin.readlines

sys.setrecursionlimit(10 ** 9)

INF = 1 << 60





def main():

    a, b, x = list(map(int, readline().split()))

    if x > a * a * b / 2:

        angle = atan(2 * (a * a * b - x) / a ** 3)

    else:

        angle = atan(a * b * b / (2 * x))



    print((angle / pi * 180))

    return





if __name__ == '__main__':

    main()

import sys

from math import atan, degrees



read = sys.stdin.read

readline = sys.stdin.readline

readlines = sys.stdin.readlines

sys.setrecursionlimit(10 ** 9)

INF = 1 << 60





def main():

    a, b, x = list(map(int, readline().split()))

    if x > a * a * b / 2:

        print((degrees(atan(2 * (a * a * b - x) / a ** 3))))

    else:

        print((degrees(atan(a * b * b / (2 * x)))))



    return





if __name__ == '__main__':

    main()

import sys
from math import atan, pi

read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
sys.setrecursionlimit(10**9)
INF = 1 << 60


def main():
    a, b, x = list(map(int, readline().split()))
    if x > a * a * b / 2:
        angle = atan(2 * (a * a * b - x) / a**3)
    else:
        angle = atan(a * b * b / (2 * x))
    print((angle / pi * 180))
    return


if __name__ == "__main__":
    main()

import sys
from math import atan, degrees

read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines
sys.setrecursionlimit(10**9)
INF = 1 << 60


def main():
    a, b, x = list(map(int, readline().split()))
    if x > a * a * b / 2:
        print((degrees(atan(2 * (a * a * b - x) / a**3))))
    else:
        print((degrees(atan(a * b * b / (2 * x)))))
    return


if __name__ == "__main__":
    main()

-from math import atan, pi +from math import atan, degrees -        angle = atan(2 * (a * a * b - x) / a**3) +        print((degrees(atan(2 * (a * a * b - x) / a**3)))) -        angle = atan(a * b * b / (2 * x)) -    print((angle / pi * 180)) +        print((degrees(atan(a * b * b / (2 * x)))))