# b_sum_n_by_len.py

# b_sum_n_by_len.py

from itertools import combinations

def place_combo(theLength,theList):
    aaa = [0] * theLength
    ttt = []
    zzz = len(theList)
    forLoc = range(theLength)
    for subset in combinations(forLoc, zzz):
        xyz = theList[:]
        arr = aaa[:]
        for i in subset:
            arr[i] = xyz.pop(0)
        ttt += [arr]
    ttt.sort()
    return ttt

def sum_n_by_len(n,L=None):
    if not L:
        L = n
    result = []
    ttt = []
    for i in range(n):
            t = [n-i, i]
            result.extend(place_combo(L,t))
            if i > 1:
                ttt.append(t)
    while ttt:
        carry = ttt.pop()
        n = carry[-1]
        for i in range(1,n):
            t = carry[:-1]+[n-i, i]
            result.extend(place_combo(L,t))
            if i > 1:
                ttt.append(t)
    result.sort()
    return result

zzz = sum_n_by_len(10)
for z in zzz:
    print z