merge_sort() begin. input:
input1 (22)
input2 (7)
input3 (2)
input4 (1)
input5 (8)
input6 (4)
    merge_sort() begin. input:
    input1 (22)
    input2 (7)
    input3 (2)
        merge_sort() begin. input:
        input1 (22)
        merge_sort() end. returning single element
        merge_sort() begin. input:
        input2 (7)
        input3 (2)
            merge_sort() begin. input:
            input2 (7)
            merge_sort() end. returning single element
            merge_sort() begin. input:
            input3 (2)
            merge_sort() end. returning single element
        merge_sort() end. returning:
        input3 (2)
        input2 (7)
    merge_sort() end. returning:
    input3 (2)
    input2 (7)
    input1 (22)
    merge_sort() begin. input:
    input4 (1)
    input5 (8)
    input6 (4)
        merge_sort() begin. input:
        input4 (1)
        merge_sort() end. returning single element
        merge_sort() begin. input:
        input5 (8)
        input6 (4)
            merge_sort() begin. input:
            input5 (8)
            merge_sort() end. returning single element
            merge_sort() begin. input:
            input6 (4)
            merge_sort() end. returning single element
        merge_sort() end. returning:
        input6 (4)
        input5 (8)
    merge_sort() end. returning:
    input4 (1)
    input6 (4)
    input5 (8)
merge_sort() end. returning:
input4 (1)
input3 (2)
input6 (4)
input2 (7)
input5 (8)
input1 (22)
