#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
typedef pair<int,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
//#define INF 1000000000
#define mod 1000000007
#define fi first
#define sc second
#define rep(i,x) for(int i=0;i<x;i++)
#define repn(i,x) for(int i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())
#define int long long
ll D;

template< typename flow_t, typename cost_t >
struct PrimalDual {
  const cost_t INF;

  struct edge {
    int to;
    flow_t cap;
    cost_t cost;
    int rev;
    bool isrev;
  };
  vector< vector< edge > > graph;
  vector< cost_t > potential, min_cost;
  vector< int > prevv, preve;

  PrimalDual(int V) : graph(V), INF(1000000000LL) {}

  void add_edge(int from, int to, flow_t cap, cost_t cost) {
    graph[from].emplace_back((edge) {to, cap, cost, (int) graph[to].size(), false});
    graph[to].emplace_back((edge) {from, 0, -cost, (int) graph[from].size() - 1, true});
  }

  cost_t min_cost_flow(int s, int t, flow_t f) {
    int V = (int) graph.size();
    cost_t ret = 0;
    using Pi = pair< cost_t, int >;
    priority_queue< Pi, vector< Pi >, greater< Pi > > que;
    potential.assign(V, 0);
    preve.assign(V, -1);
    prevv.assign(V, -1);

    while(f > 0) {
      min_cost.assign(V, INF);
      que.emplace(0, s);
      min_cost[s] = 0;
      while(!que.empty()) {
        Pi p = que.top();
        que.pop();
        if(min_cost[p.second] < p.first) continue;
        for(int i = 0; i < graph[p.second].size(); i++) {
          edge &e = graph[p.second][i];
          cost_t nextCost = min_cost[p.second] + e.cost + potential[p.second] - potential[e.to];
          if(e.cap > 0 && min_cost[e.to] > nextCost) {
            min_cost[e.to] = nextCost;
            prevv[e.to] = p.second, preve[e.to] = i;
            que.emplace(min_cost[e.to], e.to);
          }
        }
      }
      if(min_cost[t] == INF) return -1;
      for(int v = 0; v < V; v++) potential[v] += min_cost[v];
      flow_t addflow = f;
      for(int v = t; v != s; v = prevv[v]) {
        addflow = min(addflow, graph[prevv[v]][preve[v]].cap);
      }
      f -= addflow;
      ret += addflow * potential[t];
      ret += addflow * D;
      for(int v = t; v != s; v = prevv[v]) {
        edge &e = graph[prevv[v]][preve[v]];
        e.cap -= addflow;
        graph[v][e.rev].cap += addflow;
      }
    }
    return ret;
  }

  void output() {
    for(int i = 0; i < graph.size(); i++) {
      for(auto &e : graph[i]) {
        if(e.isrev) continue;
        auto &rev_e = graph[e.to][e.rev];
        cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/" << rev_e.cap + e.cap << ")" << endl;
      }
    }
  }
};

int n,m;
vector<P>edge[105];
int dp[105];

int calc(int v){
	if(dp[v] >= 0) return dp[v];
	dp[v] = 0;
	if(v == n-1) return dp[v];
	for(int i=0;i<edge[v].size();i++){
		dp[v] = max(dp[v],calc(edge[v][i].fi)+edge[v][i].sc);
	}
	return dp[v];
}

signed main(){
	cin>>n>>m;
	rep(i,m){
		int x,y,s; cin>>x>>y>>s;
		edge[x].pb(mp(y,s));
	}
	memset(dp,-1,sizeof(dp));
	D = calc(0);
	ll ans = 0;
	PrimalDual<int,int>g(n);
	rep(i,n){
		rep(j,edge[i].size()){
			int u = i,v = edge[i][j].fi,cs = edge[i][j].sc;
			ans += 200000-cs;
			g.add_edge(v,u,1,-200000);
			g.add_edge(v,u,1e9,-cs);
		}
	}
	ans += g.min_cost_flow(n-1,0,1e9);
	ll ans2 = 0;
	rep(i,n){
		rep(j,edge[i].size()){
			int u = i,v = edge[i][j].fi,cs = edge[i][j].sc;
			ans2 += g.potential[v]-g.potential[u]-cs; 
			assert(g.potential[v]-g.potential[u]-cs >= 0);
			edge[i][j].sc = g.potential[v]-g.potential[u];
		}
	}
	memset(dp,-1,sizeof(dp));
	ll DD = calc(0);
	assert(ans == ans2);
	assert(D == DD);
	cout << ans << endl;
}


Measured memory_bytes: 3308