const

max=100000;

type

we=array[1..max]of longint;

var

v,u,w,f:we;

i,a,n,m,b,s,p:longint;

procedure swap(x,y:longint);

var

ls:longint;

begin

ls:=w[x];

w[x]:=w[y];

w[y]:=ls;

ls:=v[x];

v[x]:=v[y];

v[y]:=ls;

ls:=u[x];

u[x]:=u[y];

u[y]:=ls;

end;

procedure qsort(l,r:longint);

var

xl,xr:longint;

x:longint;

begin

x:=w[(l+r)div 2];

xl:=l;

xr:=r;

if xl<xr then

begin

while w[xl]<x do inc(xl);

while w[xr]>x do dec(xr);

if xl<=xr then

begin

swap(xl,xr);

inc(xl);dec(xr);

end;

end;

if xr>l then qsort(l,xr);

if xl<r then qsort(xl,r);

end;

procedure ins;

begin

readln(m,n);

for i:=1 to n do

begin

readln(a,b,s);

u[i]:=a;

v[i]:=b;

w[i]:=s;

end;

qsort(1,n);

end;

procedure chushi;

begin

for i:=1 to n do

begin

f[u[i]]:=u[i];

f[v[i]]:=v[i];

end;

end;

function getfather(var x:longint):longint;

var

y:longint;

begin

y:=x;

while f[x]<>x do x:=f[x];

f[y]:=x;

exit(x);

end;

procedure hb(x,y:longint);

var

fx,fy:longint;

begin

fx:=getfather(x);

fy:=getfather(y);

f[fx]:=fy;

end;

procedure main;

var

xx:longint;

begin

p:=0;

xx:=0;

i:=0;

while xx<m-1do begin

i:=i+1;

if (getfather(u[i]))<>(getfather(v[i])) then

begin

p:=p+w[i];

xx:=xx+1;

hb(u[i],v[i]);

end;

end;

end;

procedure print;

begin

writeln(p);

end;

begin

ins;

chushi;

main;

print;

end.