Use 15 identical sticks to form a triangle, and all the sticks must be assembled. How many spellings are there? (Listed in order, represented by addition formula, such as 6+6+3)
用15根相同的小棒拼成一个三角形，全部小棒都要拼完，有多少种拼法？(按顺序列举，用加法算式表示，如6+6+3)
<result>7</result>