#include<bits/stdc++.h>
using namespace std;
const int N=2e5+5;
const int M=5e5+5;

static char buf[1000000],*p1=buf,*p2=buf;
#define getchar() p1==p2&&(p2=(p1=buf)+fread(buf,1,1000000,stdin),p1==p2)?EOF:*p1++
inline int wrd(){int x=0,f=1;char c=getchar();while(c<'0' || c>'9'){if(c=='-') f=-1;c=getchar();}while(c>='0' && c<='9') {x=(x<<3)+(x<<1)+c-48;c=getchar();}return x*f;}
inline void write(long long x){static char buf[20];static int len=-1;if(x<0)putchar('-'),x=-x;do buf[++len]=x%10,x/=10;while(x);while(len>=0)putchar(buf[len--]+48);}

int n,m,fa[N];
long long as;
struct nd{int u,v,w;}a[M];

int fd(int x){return x==fa[x]?x:fa[x]=fd(fa[x]);}
void uty(int x,int y){fa[fd(x)]=fd(y);}

signed main(){
	n=wrd(),m=wrd(),iota(fa+1,fa+n+1,1);
	for(int i=1;i<=m;++i) a[i]={wrd(),wrd(),wrd()};
	sort(a+1,a+m+1,[&](nd a,nd b){return a.w<b.w;});
	for(int i=1;i<=m;++i) if(fd(a[i].u)^fd(a[i].v)) uty(a[i].u,a[i].v),as+=a[i].w;
	write(as);
}