type mch=record x,y:integer end;
var fi:text;
    f:array[1..1001,1..1001] of longint;
    a :array[1..1001,0..1001] of integer;
    c:array[1..1001,1..1001] of integer;
    verymax,max,cap,ns,x1,n,i,m,j,k,eps,s,t,p,q,llant:integer;
    lant,viz,cq,zzz:array[1..1001] of integer;
    sol:array[1..1001] of integer;
    vec:array[1..1001] of mch;

procedure citire;
begin
assign(fi,'critice.in'); reset(Fi);
readln(fi,n,m);
for k:=1 to m do
 begin
 readln(fi,i,j,cap);
 inc(a[i,0]); a[i,a[i,0]]:=j;
 inc(a[j,0]); a[j,a[j,0]]:=i;
 c[i,j]:=cap;
 c[j,i]:=cap;
 vec[k].x:=i; vec[k].Y:=j;
 end;
close(Fi);
end;

function bf:boolean;
var i,vf:integer;
begin
fillchar(viz,sizeof(viz),0);
viz[s]:=-1;
cq[1]:=s; p:=1; q:=1;
while (q<=p)and(viz[t]=0) do
 begin
 vf:=cq[q];
 for i:=1 to n do
  if (c[vf,i]>0)and(viz[i]=0) and
   ( (f[vf,i]<c[vf,i]) or (f[i,vf]>0)) then
      begin
      inc(p);
      cq[p]:=i;
      viz[i]:=vf;
      if i=t then break;
      end;
 inc(q);
 end;
if viz[t]<>0 then
  begin
  bf:=true;
  eps:=maxint;
  llant:=0; i:=t;
  while i<>-1 do
   begin
if viz[i]<>-1 then   if (f[viz[i],i]>=0)and(c[viz[i],i]-f[viz[i],i]<eps) then
      eps:=c[viz[i],i]-f[viz[i],i]
      else if (f[i,viz[i]]>0)and(f[i,viz[i]]<eps) then eps:=f[i,viz[i]];
   inc(llant);
   lant[llant]:=i;
   i:=viz[i];
   end;
   end else bf:=false;
end;

procedure flux_max;
var i:integer;
begin
fillchar(f,sizeof(f),0);
while bf do
 begin
 for i:=llant downto 2 do
  if (f[lant[i],lant[i-1]]<=0) then
  begin
    inc(f[lant[i],lant[i-1]],eps);
    f[lant[i-1],lant[i]]:=-f[lant[i],lant[i-1]];
    end
   else
   begin
   dec(f[lant[i-1],lant[i]],eps);
   f[lant[i],lant[i-1]]:=-f[lant[i-1],lant[i]];
   end;
  inc(max,eps);
 end;
end;

procedure afis;
begin
assign(fi,'critice.out'); rewrite(Fi);
writeln(fi,ns);
for i:=1 to ns do  writeln(Fi,sol[i]);
close(fi);
end;

begin
citire;
max:=0;
s:=1; t:=n;
flux_max;
verymax:=max;
for i:=1 to m do
   begin
   max:=0;
   inc(c[vec[i].x,vec[i].y]);
   inc(c[vec[i].y,vec[i].x]);
   flux_max;
   if max>verymax then
     begin
     inc(ns);
     sol[ns]:=i;
     end;
   dec(c[vec[i].x,vec[i].y]);
   dec(c[vec[i].y,vec[i].x]);
   end;
afis;
end.