Fractions: addition and subtraction#9425
Two fractions are given. Find their sum or difference.
Each line contains an example of addition or subtraction of fractions. The numerator and denominator of each fraction is a natural number not greater than 10^9.
For each input example, output the answer on a separate line as an irreducible fraction. If the answer is negative, a minus sign should appear in front of the fraction.
Example 1