T=20;
n=[2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2];
a=[629,748,276,828,23,524,80,200,532,677,571,916,256,512,260,130,971,20,129,763,488,694,505,170,56,607,848,424,357,315,787,198,518,300,666,237,537,776,458,916];