from fractions import Fraction

vfunc = lambda x: Fraction(2, int(x))
V1, V2, V3 = (vfunc(input()) for _ in range(3))

t_12_a = 2 / (V1 + V2)
t_12_b = 2 / (V1 - V2)
t_23_a = 2 / (V2 + V3)
t_23_b = 2 / (V2 - V3)

fra_lcm = lambda x, y: (x / y).numerator * y
t = min(fra_lcm(t_12_a, t_23_a),
        fra_lcm(t_12_a, t_23_b),
        fra_lcm(t_12_b, t_23_a),
        fra_lcm(t_12_b, t_23_b))
print(t if t.denominator != 1 else f'{int(t)}/1')