var f,g:text;
    n,m,i,a,b,c,s:integer;
begin
assign (f,'flux.in');
assign (g,'flux.out');
reset (f);
rewrite (g);
readln (f,n);
readln (f,m);
s:=0;
for i:=1 to m do
begin
readln (f,a,b,c);
if b=n
then
    s:=s+c;
end;
writeln (g,s);
close(f);
close(g);
end.