v = 3.times.map{ 1r / gets.to_i}
dv = 2.times.map{|i| 1r / (v[i] - v[i+1])}
l = dv[0].denominator.lcm(dv[1].denominator)
n = 2.times.map{|i| dv[i].numerator * l / dv[i].denominator}
ans = 1r * n[0].lcm(n[1]) / l
puts "#{ans.numerator}/#{ans.denominator}"