{"trustable":false,"sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\u003cdiv\u003e\u003cp\u003eYixght is a manager of the company called SzqNetwork(SN). Now she\u0027s very worried because she has just received a bad news which denotes that DxtNetwork(DN), the SN\u0027s business rival, intents to attack the network of SN. More unfortunately, the original network of SN is so weak that we can just treat it as a tree. Formally, there are \u003ci\u003eN\u003c/i\u003e nodes in SN\u0027s network, \u003ci\u003eN\u003c/i\u003e-1 bidirectional channels to connect the nodes, and there always exists a route from any node to another. In order to protect the network from the attack, Yixght builds \u003ci\u003eM\u003c/i\u003e new bidirectional channels between some of the nodes.\u003c/p\u003e\u003cp\u003eAs the DN\u0027s best hacker, you can exactly destory two channels, one in the original network and the other among the \u003ci\u003eM\u003c/i\u003e new channels. Now your higher-up wants to know how many ways you can divide the network of SN into at least two parts.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\u003cdiv\u003e\u003cp\u003eThe first line of the input file contains two integers: \u003ci\u003eN\u003c/i\u003e (1 \u0026le; \u003ci\u003eN\u003c/i\u003e \u0026le; 100 000), \u003ci\u003eM\u003c/i\u003e (1 \u0026le; \u003ci\u003eM\u003c/i\u003e \u0026le; 100 000) — the number of the nodes and the number of the new channels.\u003c/p\u003e\u003cp\u003eFollowing \u003ci\u003eN\u003c/i\u003e-1 lines represent the channels in the original network of SN, each pair (\u003ci\u003ea\u003c/i\u003e,\u003ci\u003eb\u003c/i\u003e) denote that there is a channel between node \u003ci\u003ea\u003c/i\u003e and node \u003ci\u003eb\u003c/i\u003e.\u003c/p\u003e\u003cp\u003eFollowing \u003ci\u003eM\u003c/i\u003e lines represent the new channels in the network, each pair (\u003ci\u003ea\u003c/i\u003e,\u003ci\u003eb\u003c/i\u003e) denote that a new channel between node \u003ci\u003ea\u003c/i\u003e and node \u003ci\u003eb\u003c/i\u003e is added to the network of SN.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\u003cp\u003eOutput a single integer — the number of ways to divide the network into at least two parts.\u003c/p\u003e\u003c/div\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e4 1\r\n1 2\r\n2 3\r\n1 4\r\n3 4\r\n\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e3\u003c/pre\u003e"}}]}