公式出现＂B＂处写一个选股公式

请老师在公式出现"B"处写一个选股公式。谢谢！

买线:EMA(C,2),pointdot,color0000DD;
卖线:EMA(SLOPE(C,21)*20+C,42),pointdot,color00DD00;
BU:=cross(买线,卖线);
SEL:=cross(卖线,买线);
drawtext(bu,LOW*0.99,'B'),colorCC00ff,linethick1;
drawtext(sel,HIGH*1.04,'S'),color00CC00,linethick1;
stickline(买线>=卖线,low,high,0.1,0),color0000CC;
stickline(买线>=卖线,close,open,7,0),color0000CC;

stickline(买线<卖线,close,open,7,0),colorCCCC00;
stickline(买线<卖线,low,high,0.1,0),colorCCCC00;

stickline(cross(买线,卖线),open,close,7,0),colorDD00DD;
stickline(cross(卖线,买线),open,close,7,0),color00DD00;

买线:=EMA(C,2);
卖线:=EMA(SLOPE(C,21)*20+C,42);
BU:cross(买线,卖线);