#yuki_356
import fractions

t1=int(raw_input())
t2=int(raw_input())
t3=int(raw_input())

d=t1*t2*t3
n1=(t3-t1)*t2
n2=(t2-t1)*t3
n=fractions.gcd(n1,n2)
g=fractions.gcd(n,d)
print "%d/%d" % (d/g,n/g)