#!/bin/ruby

n,m = gets.strip.split(' ')
n = n.to_i
m = m.to_i

def minimum_cuts(n,m)
    if n <= 0 || m <= 0
        puts 0
    elsif n == 1
        puts m-1
    elsif m == 1
        puts n - 1
    elsif m > n
        mini_cuts(n,m)
    else
        mini_cuts(m,n)
    end
end

def mini_cuts(small,big)
    puts (small-1) * (big-1)
end


minimum_cuts(n,m)