ll@n,m=1<=4?-1:1: b==n-1?(x&3)==0||(x&3)==3?2:-2 : b&1?-1:1; }else{ a[x]= z==0?0:z&z-1?0: b<2?(x&3)==2||(y&3)==2?1:-1: b&1?-1:1; } a[x]*=BIT_popcount((x|y)>>2)&1^(y