//#![allow(unused)]
#[allow(unused_imports)]
use std::{
    cell::RefCell, convert::{Infallible, TryFrom, TryInto as _},
    fmt::{self, Debug, Display, Formatter,}, fs::{File}, hash::{Hash, Hasher},
    iter::{Product, Sum}, marker::PhantomData,
    ops::{Add, AddAssign, Sub, SubAssign, Div, DivAssign, Mul, MulAssign, Neg, RangeBounds},
    str::{FromStr, SplitWhitespace}, sync::{atomic::{self, AtomicU32, AtomicU64}, Once},
    collections::{*, btree_map::Range}, mem::{swap},
    cmp::{self, Reverse, Ordering, Eq, PartialEq, PartialOrd},
    thread::LocalKey, f64::consts::PI, time::Instant, rc::Rc,
    io::{self, stdin, Read, read_to_string, BufWriter, BufReader, stdout, Write},
};
#[allow(unused_imports)]
use proconio::{input, input_interactive, marker::{*}};
#[allow(unused_imports)]
//use rand::{thread_rng, Rng, seq::SliceRandom};
#[allow(unused_imports)]
//use ac_library::{*};

#[allow(dead_code)]
const INF: i64 = 1<<60;
#[allow(dead_code)]
const MOD: i64 = 1000000007;
#[allow(dead_code)]
const D: [(usize, usize); 4] = [(1, 0), (0, 1), (!0, 0), (0, !0)];

pub struct UnionFind{
    parent: Vec<i32>,
}

impl UnionFind{
    pub fn new(n: usize)->Self{
        UnionFind{
            parent: vec![-1; n],
        }
    }

    pub fn find(&mut self, r: usize)->usize{
        if self.parent[r] < 0{return r;}
        let p = self.find(self.parent[r] as usize);
        self.parent[r] = p as i32;
        p
    }

    pub fn union(&mut self, u: usize, v: usize){
        let (mut pu, mut pv) = (self.find(u), self.find(v));
        if pu==pv{return;}
        if self.parent[pu] > self.parent[pv]{
            swap(&mut pu, &mut pv);
        }
        self.parent[pu] += self.parent[pv];
        self.parent[pv] = pu as i32;
    }

    pub fn same(&mut self, u: usize, v: usize)->bool{
        self.find(u)==self.find(v)
    }

    pub fn size(&mut self, p: usize)->usize{
        let r = self.find(p);
        (-self.parent[r]) as usize
    }
}

//use proconio::fastout;
//#[fastout]
fn main() {
    input! {
        n: usize, m: usize,
        mut e: [(Usize1,Usize1,i64); m],
    }
    let mut uf = UnionFind::new(n);
    let mut ans = 0;
    e.sort_by(|u, v| v.2.cmp(&u.2));
    for &(u, v, w) in &e{
        if uf.same(u, v){continue}
        uf.union(u, v);
        ans += 2*w;
    }
    println!("{}", ans);
}