{"trustable":false,"sections":[{"title":"","value":{"format":"MD","content":"有一些简单化合物,每种化合物由两种元素组成。\n在N\u003e2的情况下,如果有n组化合物正好由n种物质组成,如:A – B B – C C – A 这样就会产生爆炸。\n请问每组数据的化合物会经历几次爆炸?\n"}},{"title":"输入","value":{"format":"MD","content":"多组数据读入。\n每组数据输入若干行,给出化合物的元素组成 (元素为正整数,在0~100000范围内)\n每组数据以-1结尾"}},{"title":"输出","value":{"format":"MD","content":"对于每组数据输出一行,为爆炸次数。"}},{"title":"input","value":{"format":"MD","content":"1 2\n3 4\n3 5\n3 1\n2 3\n4 1\n2 6\n6 5\n-1"}},{"title":"output","value":{"format":"MD","content":"3"}}]}