# Enter your code here. Read input from STDIN. Print output to STDOUT
def num_cuts(n, m, cache):
    if n == 1 and m == 1:
        return 0
    big_side = max(n, m)
    small_side = min(n, m)
    if small_side == 1:
        return big_side - 1
    elif (big_side, small_side) in cache:
        return cache[(big_side, small_side)]
    
    cut_point = big_side / 2
    cuts = 1 + num_cuts(cut_point, small_side, cache) + num_cuts(big_side - cut_point, small_side, cache)
    cache[(big_side, small_side)] = cuts
    return cuts
        

n, m = map(int, raw_input().strip().split(' '))
c = {}
print(num_cuts(n, m, c))