Let x1, x2, . . . , xm be real numbers satisfying the following conditions: a b) x1+x2+...+xm =b∗ aforsomeintegersaandb(a>0). Determine the maximum value of xp1 + xp2 + . . . + xpm for some even positive integer p. Input Each input line contains four integers: m, p, a, b (m ≤ 2000, p ≤ 12, p is even). Input is correct, i.e. for each input numbers there exists x1, x2, . . . , xm satisfying the given conditions. Output For each input line print one number — the maximum value of expression, given above. The answer must be rounded to the nearest integer. Sample Input 1997 12 3 -318 10 2 4 -1 Sample Output 189548 6 √ a)√1 ≤xi≤ 5; √