#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#include<string>
#include<iostream>
#include<queue>
#include<cmath>
#include<map>
#include<stack>
#include<set>
using namespace std;
#define REPF( i , a , b ) for ( int i = a ; i <= b ; ++ i )
#define REP( i , n ) for ( int i = 0 ; i < n ; ++ i )
#define CLEAR( a , x ) memset ( a , x , sizeof a )
const int INF=0x3f3f3f3f;
typedef long long LL;

const int MAXM = 100000;
const int MAXN = 1005;

struct Edge
{
    int u,v,len,next;
}edge[MAXM];

int n,m,num;
int head[MAXN],dist[MAXN],inq[MAXN];

void init()
{
    num=0;
    memset(head,-1,sizeof(head));
}

void addedge(int u,int v,int len)
{
    edge[num].u=u;
    edge[num].v=v;
    edge[num].len=len;
    edge[num].next=head[u];
    head[u]=num++;
}

void spfa()
{
    memset(dist,INF,sizeof(dist));
    memset(inq,0,sizeof(inq));
    inq[0]=1;
    dist[0]=0;
    queue<int>Q;
    Q.push(0);
    while (!Q.empty())
    {
        int u=Q.front();
        Q.pop();
        inq[u]=0;
        for (int i=head[u];~i;i=edge[i].next)
        {
            int v=edge[i].v;
            if (dist[v]>dist[u]+edge[i].len)
            {
                dist[v]=dist[u]+edge[i].len;
                if (!inq[v])
                {
                    inq[v]=1;
                    Q.push(v);
                }
            }
        }
    }
    printf("%d\n",-dist[n+1]);
}

int main()
{
    int i,j,u,v,w;
    while (~scanf("%d%d",&n,&m))
    {
        init();
        for (i=0;i<m;i++)
        {
            scanf("%d%d%d",&u,&v,&w);
            u++,v++;
            addedge(v,u,-w);
        }
        for (i=1;i<=n;i++)
        {
            addedge(0,i,0);
            addedge(i,n+1,-1);
        }
        spfa();
    }
    return 0;
}

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