\href{http://codeforces.ru/profile/sdya}{Dima} and \href{http://codeforces.ru/profile/Seyaua}{Zhenya}, two brothers - twins. Not only do they look at each other like two drops of water, so they are still sitting in the classroom at the same desk. And one of them always sits on the left, and the second - on the right. Each claims that he - Dima. Ivan Ivanovich of experience knows that the young man tells a lie to the right once out of \textbf{m}, a twin to the left - once out of \textbf{n}. But Ivan Ivanovitch interested in something quite different: what is the probability that Jack is sitting on the left? Since Ivan Ivanovich - teacher work, it is only natural that he asks for your help in solving this complex problem for him. \InputFile In a single line two natural numbers \textbf{n} and \textbf{m}, each of which is greater than one but less than \textbf{100}. \OutputFile Bring the required probability as a regular irreducible fraction in the form \textbf{a/b}, where \textbf{a} and \textbf{b} -- non-negative integers.