Find the sum of two proper fractions $a / b$ and $c / d$. Present the result as an irreducible fraction. If the result is an integer, then print only this integer. \InputFile One line contains four positive integers $a, b, c, d$ --- the numerators and denominators of the fractions. All numbers do not exceed $1000$. \OutputFile Print the numerator and denominator of the resulting fraction, or an integer if the result is a whole number.