T=20;
n=[2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2];
a=[905,870,681,466,288,4,317,634,736,368,129,387,443,629,436,683,114,342,391,969,942,157,915,59,468,18,552,495,670,94,542,984,889,258,129,939,842,361,681,393];