Question: Error, reserved word `end` unexpected

Hello, i'm writing a code but when i run it, the maple shows this msg, can someone say what is wrong?

regards,

restart;
nn := 13;
                               13
oe := 4;
num := 12;
                               12
n1 := 1;
fac := 1;
                               1
delta := 0;
                               0
X := alf;
alf0 := 1/(sum(fac^j, j = 0 .. num-1));
                               1
                               --
                               12
Y := alf;
xnH := vector(nn);
ynH := vector(nn);
for j to num+1 do;
 if j+n1-1 <= nn then                
       alf := alf0 * delta:
        if oe = 2 then
           if irem(j,2)=1 then
              xnH[j+n1-1] := eval(X);    
              ynH[j+n1-1] := eval(Y);
           else
              deltaI:=((delta-1)/fac-1)/fac;
              deltaF:=delta;
              delta:=(deltaF-deltaI)/2+deltaI;
              alf := alf0 * delta;
              xnH[j+n1-1] := eval(X);    
              ynH[j+n1-1] := eval(Y);
              delta := deltaF;
            end if;
        end if;
if oe = 3 then
              if irem(j,3)=1 then
              xnH[j+n1-1] := eval(X);    
              ynH[j+n1-1] := eval(Y);
              elif irem(j,3)=2 then
              deltaI:=((delta-1)/fac-1)/fac;
              deltaF:=delta*fac+1;
              delta:=(deltaF-deltaI)*(0.5-1/(2*sqrt(5)))+deltaI;
              alf := alf0 * delta;
              xnH[j+n1-1] := eval(X);    
              ynH[j+n1-1] := eval(Y);
              delta := (deltaF-1)/fac;
              elif irem(j,3)=0 then
              deltaI:=(((delta-1)/fac-1)/fac-1)/fac;
              deltaF:=delta;
              delta:=(deltaF-deltaI)*(0.5+1/(2*sqrt(5)))+deltaI;
              alf := alf0 * delta;
              xnH[j+n1-1] := eval(X);    
              ynH[j+n1-1] := eval(Y);
              delta := deltaF;
              end if;
end if;
        if oe = 4 then
                if irem(j,4)=1 then
                xnH[j+n1-1] := eval(X);    
                ynH[j+n1-1] := eval(Y);
                delta := delta * fac + 1;
                elif irem(j,4)=2 then
                deltaI:=((delta-1)/fac-1)/fac;
                deltaF:=(delta*fac+1)*fac+1;
                delta:=(deltaF-deltaI)*(0.5-sqrt(21)/14)+deltaI;
                alf := alf0 * delta;
                xnH[j+n1-1] := eval(X);    
                ynH[j+n1-1] := eval(Y);
                delta := (((deltaF-1)/fac)-1)/fac;
                elif irem(j,4)=3 then
                deltaI:=(((delta-1)/fac-1)/fac-1)/fac;
                deltaF:=delta*fac+1;
                delta:=(deltaF-deltaI)*(0.5)+deltaI;
                alf := alf0 * delta;
                xnH[j+n1-1] := eval(X);    
                ynH[j+n1-1] := eval(Y);
                delta := (deltaF-1)/fac;end if:
                elif irem(j,4)=0 then
                deltaI:=((((delta-1)/fac-1)/fac-1)/fac-1)/fac;
                deltaF:=delta;
                delta:=(deltaF-deltaI)*(0.5+sqrt(21)/14)+deltaI;
                alf := alf0 * delta;
                xnH[j+n1-1] := eval(X);    
                ynH[j+n1-1] := eval(Y);
                delta := deltaF;
                end if;
       end if;
end if;
od;