exitcode=217的一段程序，请教大神哪里错了

uses math;
var i,j,n,m,p:longint;
    a:array[1..60,1..2] of longint;
    w,c:array[0..60] of longint;
    b:array[1..60] of -1..2;
    f:array[1..32000] of longint;
begin
{assign(input,'happy.in');
assign(output,'happy.out');
reset(input);
rewrite(output);}
readln(m,n);
for i:=1 to n do
    begin
    readln(c[i],w[i],p);
    if p>0 then
       begin
       inc(b[p]);
       a[p,b[p]]:=i;
       b[i]:=-1;
       end;
    end;
for i:=1 to n do
    for j:=m downto 0 do
        if (j-c[i]>=0)and(b[i]>-1) then
           begin
           f[j]:=max(f[j],f[j-c[i]]+c[i]*w[i]);
           f[j]:=max(f[j],f[j-c[i]]+c[i]*w[i]+c[a[j,1]]*w[a[j,1]]);
           f[j]:=max(f[j],f[j-c[i]]+c[i]*w[i]+c[a[j,2]]*w[a[j,2]]);
           f[j]:=max(f[j],f[j-c[i]]+c[i]*w[i]+c[a[j,1]]*w[a[j,1]]+c[a[j,2]]*w[a[j,2]]);
           end;
write(f[m]);
close(input);
close(output);
end.