program CCC_2003_s5l;

uses math;

var i,xx,yy,ww,cities,roads,dests,max_weight,now_node,sign,max:longint;
map:array[0..1000,0..1000] of longint;
visited:array[0..1000] of boolean;
weight,mubiao:array[0..1000] of longint;

procedure swap(var pa,pb:longint);
var tmp:longint;
begin
tmp:=pa;
pa:=pb;
pb:=tmp;
end;

begin
assign(input,'s5.in');
reset(input);
readln(cities,roads,dests);
for i:=1 to roads do
begin
readln(xx,yy,ww);
if xx>yy then swap(xx,yy);
if ww>map[xx,yy] then
begin
map[xx,yy]:=ww;
map[yy,xx]:=ww;
end;
end;
fillchar(mubiao,sizeof(mubiao),false);
for i:=1 to dests do
readln(mubiao[i]);
fillchar(weight,sizeof(weight),0);

weight[1]:=maxlongint;
now_node:=1;

repeat
sign:=now_node;
visited[now_node]:=true;
now_node:=-1;
max:=0;
for i:=1 to cities do
begin
if (min(weight[sign],map[sign,i])>weight[i]) then
weight[i]:=min(weight[sign],map[sign,i]);
if (weight[i]>=max) and not visited[i] then
begin
max:=weight[i];
now_node:=i;
end;
end;
weight[now_node]:=max_weight;
until now_node=-1;

max:=maxlongint;
for i:=1 to dests do
if weight[mubiao[i]]<max then max:=weight[mubiao[i]];
writeln(max);
end.

Er...mind telling us a bit more about your program, what algorithm it is implementing, any debugging you have done so far, etc...

Try fixing this yourself first, then if you can't seem to get it working, tell us what you encountered so far and then ask us for help.