from math import gcd

a = int(input())
b = int(input())
c = int(input())
l = 1
for x in [a, b, c]:
    l = l * x // gcd(l, x)

g = 0
for x in [a, b, c]:
    g = gcd(g, l // x - 1)

x = gcd(l, g)
print(l // x, g // x, sep="/")