#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ff(i,a,b) for(int i=a;i<=b;i++)
#define fb(i,b,a) for(int i=b;i>=a;i--)
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair<int,int> pii;
const int maxn = 100005;
const int inf = 1e9 + 5;
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k) print the k-th smallest number in os(0-based)
int n, m;
vector<int> g[maxn];
vector<ll> cost[maxn];
ll dist[maxn];
void dij(int s){
ff(i,1,n)dist[i] = inf;
priority_queue<pii, vector<pii>, greater<pii>> pq;
pq.push({dist[s] = 0, s});
while(!pq.empty()){
pii v = pq.top(); pq.pop();
if(dist[v.se] < v.fi)continue;
for(auto u : g[v.se]){
ll w = cost[u].back(); cost[u].pop_back();
if(dist[u] > v.fi + w){
dist[u] = v.fi + w;
pq.push({dist[u], u});
}
}
}
}
int main()
{
ios::sync_with_stdio(false);
cout.tie(nullptr);
cin.tie(nullptr);
cin >> n >> m;
ff(i,1,m){
int u, v;
ll w;
cin >> u >> v >> w;
g[v].pb(u);
cost[u].pb(w);
}
ff(i,1,n)sort(all(cost[i]));
dij(n);
cout << dist[1] << endl;
return 0;
}
/**
4 5
1 2 2
2 4 2
1 3 10
3 4 7
1 4 7
// probati bojenje sahovski ili slicno
**/
