// Slower C++ solution:
#include <algorithm>

#include <iostream>

#include <cstring>

#include <cstdio>

#include <vector>

#include <queue>

#include <cmath>

#define LP_SIZE 2005

#define INF 105

#define eps 1e-8



using namespace std;

int sgn(double a) { return (a<-eps)?-1:(a>eps); }

struct SIMPLEX {

	double A[LP_SIZE][LP_SIZE], b[LP_SIZE], c[LP_SIZE], OC[LP_SIZE];

	int N[LP_SIZE], B[LP_SIZE], n, m;

	double v, x[LP_SIZE];

	int ANS_NO, ANS_OK, ANS_INF;



	SIMPLEX() { ANS_NO=0, ANS_OK=1, ANS_INF=2; }



	void clear()

	{

		memset(A, 0, sizeof(A));

		memset(c, 0, sizeof(c));

		memset(b, 0, sizeof(b));

	}



	void pivot(int l, int e)

	{

		int i, j, x, y;

		b[e] = b[l] / A[l][e];

		A[e][l] = 1.0 / A[l][e];

		for (i=1; i<=n; i++) if (y=N[i], y!=e) A[e][y] = A[l][y] / A[l][e];



		for (j=1; j<=m; j++)

			if (x=B[j], x!=l)

			{

				b[x] = b[x] - A[x][e] * b[e];

				for (i=1; i<=n; i++) if (y=N[i], y!=e) A[x][y] = A[x][y] - A[e][y] * A[x][e];

				A[x][l] = -A[x][e] * A[e][l];

			}



		v += b[e] * c[e];

		c[l] = - A[e][l] * c[e];

		for (i=1; i<=n; i++) if (y=N[i], y!=e) c[y] = c[y] - A[e][y] * c[e];



		for (i=1; i<=n; i++) if (N[i]==e) N[i]=l;

		for (j=1; j<=m; j++) if (B[j]==l) B[j]=e;

	}



	int opt()

	{

		for (int l=0, e=0, i, j, x, y, tl; 1; )

		{

			for (i= 1; i<= n; i++) if (sgn(c[N[i]])==1) break;

			if (i>n) return ANS_OK;



			double best=-1e30;

			for (i=1; i<=n; i++)

				if (y=N[i], sgn(c[y])==1)

				{

					double now=1e30, tmp;

					for (j=1; j<=m; j++)

						if (x=B[j], sgn(A[x][y])==1)

						{

							tmp=b[x] / A[x][y];

							if (now>tmp || (now==tmp && tl>x)) now=tmp, tl=x;

						}

					if ((now*c[N[i]]>best) || (now*c[N[i]]>=best-eps && y<e))

						best=now*c[N[i]], l=tl, e=y;

				}

			if (best<=-1e29) return ANS_INF;

			pivot(l, e);

		}

	}



	void delete0()

	{

		int i, j;

		for (j=1; j<=m; j++) if (B[j]==0) break;

		if (j<=m)

		{

			for (i=1; i<=n; i++) if (sgn(A[0][N[i]])) break;

			pivot(0, N[i]);

		}

		for (i=1; i<=n && N[i]; i++) ;

		for (n--; i<=n; i++) N[i]=N[i+1];

	}



	int init()

	{

		int i, j, x, y, l=0;

		for (i=1; i<=n; i++) N[i]=i;

		for (j=1; j<=m; j++) B[j]=n+j;

		v=0;



		for (j=1; j<=m; j++) if (l==0 || b[B[j]]<b[l]) l=B[j];

		if (sgn(b[l])>=0) return ANS_OK;



		memcpy(OC, c, sizeof(OC));

		memset(c, 0, sizeof(c));

		c[0]=-1; N[++n]=0;

		for (j=1; j<=m; j++) A[B[j]][0]=-1;



		if (pivot(l, 0), opt(), sgn(v)<0) return ANS_NO;

		delete0();

		memcpy(c, OC, sizeof(c));



		for (j=1; j<=m; j++)

			if (x=B[j], sgn(c[x]))

			{

				v += c[x] * b[x];

				for (i=1; i<=n; i++) y=N[i], c[y] -= A[x][y] * c[x];

				c[x]=0;

			}

		return ANS_OK;

	}



	double simplex()

	{

		init();

		opt();

		return v;

		//for (int j=1; j<=m; j++) x[B[j]]=b[B[j]];

		//for (int i=1; i<=n; i++) printf("x[%d] = %.2f\n", i, x[i]);

		//for (int i=1; i<=n; i++) printf("%.3f%c", x[i], i==n?'\n':' ');

		//return ANS_OK;

	}

}	slx;

void _add(int j, int i, int x) { slx.A[j][i]=x; }



vector <int> vec[INF], dis[INF];

void _addedge(int i, int j, int d) { vec[i].push_back(j); dis[i].push_back(d); }

int Ind[INF], Dis[INF];



int Top_sort(int n)

{

	queue <int> q;

	for (q.push(1), Dis[1]=0; q.empty()==0; )

	{

		n=q.front(), q.pop();

		for (int i=0; i<vec[n].size(); i++)

		{

			int j=vec[n][i];

			Dis[j]=max(Dis[j], Dis[n]+dis[n][i]);

			if (--Ind[j]==0) q.push(j);

		}

	}

	return Dis[n];

}

int main()

{

	//freopen("1.txt", "r", stdin);

	//freopen("2.txt", "w", stdout);



	int n, m, i;

	scanf("%d %d", &n, &m);



	double ans=0;

	for (i=1; i<=m; i++)

	{

		int x, y, z;

		scanf("%d %d %d", &x, &y, &z);

		++x, ++y, ++Ind[y], ans-=z;

		_addedge(x, y, z);

		

		_add(i+n, x, 1);

		_add(i+n, y, -1);

		slx.b[i+n]=-z; slx.c[x]-=1; slx.c[y]+=1;

	}



	_add(m+n+1, n, 1);

	slx.b[m+n+1]=Top_sort(n);

	slx.n=n; slx.m=m+1;

	

	printf("%.0f\n", ans+slx.simplex());



	return 0;

}

// Faster C++ solution for the same problem (measured speedup: 1.1244938356958363x):
#include<cstdio>

#include<cstring>

#include<queue>

#include<algorithm>

#include<vector>

#include<utility>

#include<functional>

using namespace std;

const int INF=1e9;

const int ADD=1200;

typedef pair<int,int> P;

struct edge

{

    int to,cap,cost,rev;

};

int V;

vector<edge> G[505];

int h[505];

int dist[505];

int prevv[505],preve[505];

void add_edge(int from,int to,int cap,int cost)

{

    edge tmp;

    tmp.to=to,tmp.cap=cap,tmp.cost=cost,tmp.rev=G[to].size();

    G[from].push_back(tmp);

    tmp.to=from,tmp.cap=0,tmp.cost=-cost,tmp.rev=G[from].size()-1;

    G[to].push_back(tmp);

}

int min_cost_flow(int s,int t,int f)

{

    int res=0;

    fill(h,h+V,0);

    while(f>0)

    {

        priority_queue<P,vector<P>,greater<P>> que;

        fill(dist,dist+V,INF);

        dist[s]=0;

        que.push(P(0,s));

        while(!que.empty())

        {

            P p=que.top();

            que.pop();

            int v=p.second;

            if(dist[v]<p.first)

            {

                continue;

            }

            for(int i=0;i<G[v].size();++i)

            {

                edge &e=G[v][i];

                if(e.cap>0&&dist[e.to]>dist[v]+e.cost+h[v]-h[e.to])

                {

                    dist[e.to]=dist[v]+e.cost+h[v]-h[e.to];

                    prevv[e.to]=v;

                    preve[e.to]=i;

                    que.push(P(dist[e.to],e.to));

                }

            }

        }

        if(dist[t]==INF)

        {

            return -1;

        }

        for(int v=0;v<V;++v)

        {

            h[v]+=dist[v];

        }

        int d=f;

        for(int v=t;v!=s;v=prevv[v])

        {

            d=min(d,G[prevv[v]][preve[v]].cap);

        }

        f-=d;

        res+=d*h[t];

        for(int v=t;v!=s;v=prevv[v])

        {

            edge &e=G[prevv[v]][preve[v]];

            e.cap-=d;

            G[v][e.rev].cap+=d;

        }

    }

    return res;

}

int N,M,s,t;

int indree[520],outdree[520];

int main()

{

    scanf("%d%d",&N,&M);

    V=N+2;

    t=N+1;

    int total=0;

    for(int i=1;i<=M;++i)

    {

        int x,y,z;

        scanf("%d%d%d",&x,&y,&z);

        ++x,++y;

        add_edge(x,y,INF,-z);

        outdree[x]++,indree[y]++;

        total+=z;

    }

    int max_f=0;

    for(int i=1;i<=N;++i)

    {

        if(indree[i]>outdree[i])

        {

            add_edge(s,i,indree[i]-outdree[i],0);

            max_f+=indree[i]-outdree[i];

        }

        else

        {

            add_edge(i,t,outdree[i]-indree[i],0);

        }

    }

    min_cost_flow(1,N,1);

    add_edge(N,1,INF,-dist[N]);

    int ans=min_cost_flow(s,t,max_f);

    printf("%d\n",ans-total);

    return 0;

}