#!/usr/bin/env python3
import itertools
from fractions import Fraction
import math
def lcm(a, b):
    return a * b // math.gcd(a, b)
def qlcm(p, q):
    a = p.numerator * q.denominator
    b = p.denominator * q.numerator
    c = p.denominator * q.denominator
    return Fraction(lcm(a, b), c)
t1 = int(input())
t2 = int(input())
t3 = int(input())
v1 = Fraction(2, t1)
v2 = Fraction(2, t2)
v3 = Fraction(2, t3)
ans = min([
    qlcm(2 / abs(v1 + v2), qlcm(2 / abs(v2 + v3), 2 / abs(v3 + v1))),
    qlcm(2 / abs(v1 + v2), qlcm(2 / abs(v2 + v3), 2 / abs(v3 - v1))),
    qlcm(2 / abs(v1 + v2), qlcm(2 / abs(v2 - v3), 2 / abs(v3 + v1))),
    qlcm(2 / abs(v1 + v2), qlcm(2 / abs(v2 - v3), 2 / abs(v3 - v1))),
    qlcm(2 / abs(v1 - v2), qlcm(2 / abs(v2 + v3), 2 / abs(v3 + v1))),
    qlcm(2 / abs(v1 - v2), qlcm(2 / abs(v2 + v3), 2 / abs(v3 - v1))),
    qlcm(2 / abs(v1 - v2), qlcm(2 / abs(v2 - v3), 2 / abs(v3 + v1))),
    qlcm(2 / abs(v1 - v2), qlcm(2 / abs(v2 - v3), 2 / abs(v3 - v1))),
    ])
print('%d/%d' % (ans.numerator, ans.denominator))