Find the Simplest Fraction Between Two Given Fractions

Given four positive integers (a,, b,, c,, d) representing two fractions (\frac{a}{b}) and (\frac{c}{d}) with (\frac{a}{b} < \frac{c}{d}), your task is to find an irreducible (simplest) fraction (\frac{p}{q}) such that

[ \frac{a}{b} < \frac{p}{q} < \frac{c}{d}, ]

where if multiple solutions exist, choose the one with the smallest denominator (q); if there is still a tie, choose the one with the smallest numerator (p).

You may assume that such a fraction always exists.

inputFormat

The input consists of a single line containing four space-separated positive integers: (a), (b), (c), (d). It is guaranteed that (\frac{a}{b} < \frac{c}{d}).

outputFormat

Output a single line representing the simplest fraction (\frac{p}{q}) (with no spaces) that satisfies the condition (\frac{a}{b} < \frac{p}{q} < \frac{c}{d}).

sample

1 2 3 4

2/3