With 70 yuan, I bought four kinds of books A, B, C, and D, totaling 10 volumes. It is known that the prices of four books A, B, C, and D are 3 yuan, 5 yuan, 7 yuan, and 11 yuan respectively, and at least one book of each book has been bought. So how many different purchasing methods are there?
用70元钱买了甲、乙、丙、丁四种书，共10册．已知甲，乙，丙，丁四种书每本价格分别为3元，5元，7元，11元，而且每种书至少买了一本．那么共有多少种不同的购买方法．
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