You have two positive integers w and h. Your task is to count the number of rhombi which have the following properties: 

  * Have positive area. 
  * With vertices at integer points. 
  * All vertices of the rhombi are located inside or on the border of the rectangle with vertices at points (0, 0), (w, 0), (w, h), (0, h). In other words, for all vertices (xi, yi) of the rhombus the following conditions should fulfill: 0 ≤ xi ≤ w and 0 ≤ yi ≤ h. 
  * Its diagonals are parallel to the axis. 



Count the number of such rhombi.

Let us remind you that a rhombus is a quadrilateral whose four sides all have the same length.

Input

The first line contains two integers w and h (1 ≤ w, h ≤ 4000) — the rectangle's sizes.

Output

Print a single number — the number of sought rhombi.

Please do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use cin, cout streams or the %I64d specifier.

Examples

Input

2 2


Output

1


Input

1 2


Output

0

Note

In the first example there exists only one such rhombus. Its vertices are located at points (1, 0), (2, 1), (1, 2), (0, 1).
"""
    Template written to be used by Python Programmers.
    Use at your own risk!!!!
    Owned by adi0311(rating - 5 star at CodeChef and Specialist at Codeforces).
"""
import sys
from functools import lru_cache, cmp_to_key
from heapq import merge, heapify, heappop, heappush, nlargest, nsmallest, _heapify_max, _heapreplace_max
from math import ceil, floor, gcd, fabs, factorial, fmod, sqrt, inf, log
from collections import defaultdict as dd, deque, Counter as c
from itertools import combinations as comb, permutations as perm
from bisect import bisect_left as bl, bisect_right as br, bisect
from fractions import Fraction
# sys.setrecursionlimit(2*pow(10, 6))
# sys.stdin = open("input.txt", "r")
# sys.stdout = open("output.txt", "w")
mod = pow(10, 9) + 7
mod2 = 998244353
def data(): return sys.stdin.readline().strip()
def out(var): sys.stdout.write(str(var))
def outln(var): sys.stdout.write(str(var)+"\n")
def l(): return list(sp())
def sl(): return list(ssp())
def sp(): return map(int, data().split())
def ssp(): return map(str, data().split())
def l1d(n, val=0): return [val for i in range(n)]
def l2d(n, m, val=0): return [l1d(n, val) for j in range(m)]


w, h = sp()
outln((pow(w, 2)//4) * (pow(h, 2)//4))
