You have written on a piece of paper an array of n positive integers a[1], a[2], ..., a[n] and m good pairs of integers (i1, j1), (i2, j2), ..., (im, jm). Each good pair (ik, jk) meets the following conditions: ik + jk is an odd number and 1 ≤ ik < jk ≤ n. In one operation you can perform a sequence of actions: Determine the maximum number of operations you can sequentially perform on the given array. Note that one pair may be used several times in the described operations. The first line contains two space-separated integers n, m (2 ≤ n ≤ 100, 1 ≤ m ≤ 100). The second line contains n space-separated integers a[1], a[2], ..., a[n] (1 ≤ a[i] ≤ 109) -- the description of the array. The following m lines contain the description of good pairs. The k-th line contains two space-separated integers ik, jk (1 ≤ ik < jk ≤ n, ik + jk is an odd number). It is guaranteed that all the good pairs are distinct. Output the answer for the problem.