from collections import defaultdict, deque
from heapq import heappush, heappop
from bisect import bisect_left, bisect_right
import sys
import random
import itertools
import math
sys.setrecursionlimit(10**5)
input = sys.stdin.readline
sqrt = math.sqrt


def LI(): return list(map(int, input().split()))


def LF(): return list(map(float, input().split()))


def LI_(): return list(map(lambda x: int(x)-1, input().split()))


def II(): return int(input())


def IF(): return float(input())


def LS(): return list(map(list, input().split()))


def S(): return list(input().rstrip())


def IR(n): return [II() for _ in range(n)]


def LIR(n): return [LI() for _ in range(n)]


def FR(n): return [IF() for _ in range(n)]


def LFR(n): return [LI() for _ in range(n)]


def LIR_(n): return [LI_() for _ in range(n)]


def SR(n): return [S() for _ in range(n)]


def LSR(n): return [LS() for _ in range(n)]


def gcd(x, y):
    if y == 0:
        return x
    return gcd(y, x % y)


def my_index_multi(l, x):
    return [i for i, _x in enumerate(l) if _x == x]


def sosu(x):
    for i in range(2, int(sqrt(x)+1)):
        if x % i == 0:
            return False
    return True


mod = 1000000007
inf = float('INF')


def A():
    A, B = LI()

    if A >= 1 and A <= 9 and B >= 1 and B <= 9:
        print(A*B)
    else:
        print(-1)
    return

# B


def B():
    N = II()
    if N <= 81 and N > 9:
        for i in range(2, 10):
            if N % i == 0 and N/i <= 9:
                print('Yes')
                return

    elif N > 81:
        print('No')
        return
    else:
        print('Yes')
        return
    print('No')

    return

# C


def C():
    N = II()
    
    
    L=[]
    count=0
    for i in range(2,int(sqrt(N)+2)):  
        if N%i==0:
            L.append(N/i)
            count=1
    if count==0:
        print(N-1)
    else :
        print(int(L[-1]-2+(N/L[-1])))


            

    
   

    return

# D


def D():
    
    a, b ,x = LI()
    BIG=a*a*b/2
    if x>BIG:
        y=2*b-(2*x/a/a)
        print(math.degrees(math.atan(y/a)))
    else:
        y=2*x/a/b
        print(math.degrees(math.atan(b/y)))
    return

# E


def E():
    N, M = LI()
    bit_max = 1 << N
    dp = [[inf for i in range(bit_max)] for j in range(M+1)]
    dp[0][0] = 0

    for i in range(M):
        a, b = LI()

        c = LI()
        bit = 0

        for d in c:
            bit |= 1 << (d-1)

        for w in range(bit_max):

            t = w | bit
            cost = dp[i][w] + a

            dp[i+1][t] = min(dp[i+1][t], cost)

            dp[i+1][w] = min(dp[i][w], dp[i+1][w])

    print(-1) if dp[-1][-1] == inf else print(dp[-1][-1])

    return

# F


def F():
    N, M = LI()

    value = [0] * M
    power = [0] * M
    for i in range(M):
        a, b = LI()
        value[i] = a
        c = LI()
        L = ['0'] * N
        for k in c:
            L[k - 1] = '1'
        bint = ''.join(L)
        power[i] = int(bint, 2)
    bint = ''.join(list(['1'] * N))
    dp = [inf] * (int(bint, 2)+1)
    t = 0
    cost = 0

    dp[0] = 0
    for s in range(int(bint, 2) + 1):
        for i in range(M):
            t = s | power[i]
            cost = dp[s] + value[i]
            dp[t] = min(dp[t], cost)
    print(-1) if(dp[-1] == inf) else print(dp[-1])

    return

    # you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")


def solution(S):
    # write your code in Python 3.6
    N = len(S)

    pass


# Solve
if __name__ == '__main__':
    D()


Measured memory_bytes: 40176