问一个LINGO的问题,这个程序有一行又语法错误,标出来了,那一行哪里错了啊

问一个LINGO的问题,这个程序有一行又语法错误,标出来了,那一行哪里错了啊
MODEL:
SETS:
XIA/A,B/:X1,Y1,S;
GO/1..6/:X2,Y2,D;
LI(XIA,GO):M,YU;
ENDSETS
DATA:
X1=5 2;
Y1=1 7;
X2=1.25 8.75 0.5 5.75 3 7.25;
Y2=1.25 0.75 4.75 5 6.5 7.75;
D=3 5 4 7 6 11;
ENDDATA
MIN=@SUM(LI:M*YU);
@FOR(XIA(I):@FOR(GO(J):M(I,J)=SQRT((X1(I)-X2(J))^2+(Y1(I)-Y2(J))^2)))这一行语法哪里错了啊?
@FOR(GO(I):@SUM(XIA(J):YUN(J,I))>D(I));
@FOR(XIA(I):@SUM(GO(J):YUN(I,J))