def threeSplit(a)

    s = a.sum/3
    count = 0
    s1 = 0
    s2 = 0

    (0..a.size-3).each do |cut1|
        s1 += a[cut1]
        if(s1 == s)
            s2 = 0
            ((cut1+1)..a.size-2).each do |cut2|
                s2 += a[cut2]
               if(s == s2)
                   count += 1
               end
            end
        end
    end
    count
end