{"trustable":true,"sections":[{"title":"","value":{"format":"HTML","content":"\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eAlex and Bob are brothers. Alex is the elder brother, and Bob is the younger one.\r\nSince the last New Year Day, their parents started giving them pocket money as a fee for\r\nhousehold assistance or good marks in school. The children are in the seventh heaven. They became A-students, run to the shop one ahead of another to buy some bread and clean the room in the sake of making more money. Brothers do not spend their money but store them in two separate piggy-banks: Alex wants to buy a bicycle, and Bob aims to save a million.\u003c/div\u003e\u003c/div\u003e\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eAlex is the elder brother, so he would become angry if at some moment the sum in the piggy-bank of the younger brother becomes greater than in his one. Certainly, he would break all the windows in the nearest house in such case. Bob is above all this\u0026nbsp;— he has a great aim, so such an issue is not worth breaking nerves. \u003c/div\u003e\u003c/div\u003e\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003ePoor brothers! They don\u0027t know that in fact not all their good deeds will be paid, and the sums to be given away for them are determined well ahead. Notably, during this year Alex will be given \u003ci\u003eK\u003c/i\u003e euros, and Bob will be given \u003ci\u003eM\u003c/i\u003e euros. A good deed is rewarded by giving 1 euro, and in no case the brothers would be paid simultaneously.\u003c/div\u003e\u003c/div\u003e\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eConsider \u003ci\u003eK\u003c/i\u003e good deeds of Alex and \u003ci\u003eM\u003c/i\u003e those of Bob which will be paid off and assume that every permutation of those deeds is equally probable. Find the probability for the window in the next house to remain unbroken during the year.\u003c/div\u003e\u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eIn the first line there is the number of test cases \u003ci\u003eN\u003c/i\u003e. \u003ci\u003eN\u003c/i\u003e ≤ 2004.\r\nEach of the next \u003ci\u003eN\u003c/i\u003e lines consists of two integers \u003ci\u003eK\u003csub\u003ei\u003c/sub\u003e\u003c/i\u003e and \u003ci\u003eM\u003csub\u003ei\u003c/sub\u003e\u003c/i\u003e\u0026nbsp;— the amounts of money to be paid to elder and younger brother, respectively. 0 ≤ \u003ci\u003eK\u003csub\u003ei\u003c/sub\u003e\u003c/i\u003e, \u003ci\u003eM\u003csub\u003ei\u003c/sub\u003e\u003c/i\u003e ≤ 10\u003csup\u003e4\u003c/sup\u003e.\u003c/div\u003e\u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\u003cdiv class\u003d\"problem_par\"\u003e\u003cdiv class\u003d\"problem_par_normal\"\u003eFor each test case, output the answer on a separate line with precision not less than 10\u003csup\u003e−6\u003c/sup\u003e.\u003c/div\u003e\u003c/div\u003e"}},{"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\n1 0\r\n0 1\r\n1 1\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e1\r\n0\r\n0.5\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n"}}]}