{"trustable":true,"sections":[{"title":"","value":{"format":"HTML","content":"Given a set of sticks of various lengths, is it possible to join them end-to-end to form a square?"}},{"title":"Input","value":{"format":"HTML","content":"The first line of input contains N, the number of test cases. Each test case begins with an integer 4 \u0026lt;\u003d M \u0026lt;\u003d 20, the number of sticks. M integers follow; each gives the length of a stick - an integer between 1 and 10,000. "}},{"title":"Output","value":{"format":"HTML","content":"For each case, output a line containing \"yes\" if is is possible to form a square; otherwise output \"no\". "}},{"title":"Sample","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e3\r\n4 1 1 1 1\r\n5 10 20 30 40 50\r\n8 1 7 2 6 4 4 3 5\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003eyes\r\nno\r\nyes\r\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}