#include <cstdio>
#include <cstring>

const int maxn = 1001;
const int maxm = 10000;

FILE *in = fopen("critice.in","r"), *out = fopen("critice.out","w");

struct muchie
{
	int x, y;
};

int n, m;
int a[maxn][maxn];
int f[maxn][maxn];

int viz[maxn];
int C[maxn];

muchie mc[maxm];
int crit[maxn];

void read()
{
	fscanf(in, "%d %d", &n, &m);

	for ( int i = 0; i < m; ++i )
	{
		fscanf(in, "%d %d", &mc[i].x, &mc[i].y);
		fscanf(in, "%d\n", &a[ mc[i].x ][ mc[i].y ]);

		//if ( mc[i].x != 1 && mc[i].y != 1 && mc[i].x != n && mc[i].y != n )
			a[ mc[i].y ][ mc[i].x ] = a[ mc[i].x ][ mc[i].y ];
	}
}

int findway()
{
	int p = 0, u = 0;
	memset(viz, 0, sizeof(viz));

	int x = 0;
	C[p] = 1;
	viz[C[p]] = 1;

	while ( p <= u && !viz[n] )
	{
		x = C[p++];

		for ( int i = 1; i <= n; ++i )
			if ( !viz[i] )
				if ( f[x][i] < a[x][i] )
					viz[i] = x, C[++u] = i;
				else if ( f[i][x] > 0 )
					viz[i] = -x, C[++u] = i;
	}

	return viz[n];
}

inline int min(int x, int y)
{
	return x < y ? x : y;
}

inline int abs(int x)
{
	return x < 0 ? -x : x;
}

void flux()
{
	int L[maxn];

    while ( findway() )
	{
		int lg = 0;
		L[lg] = n;

		int p = maxm << 1, q = maxm << 1, v = 0;
		while ( L[lg] != 1 )
		{
			++lg;
			L[lg] = abs(viz[ L[lg-1] ]);
			if ( viz[ L[lg-1] ] >= 0 )
				p = min(p, a[ L[lg] ][ L[lg-1] ] - f[ L[lg] ][ L[lg-1] ]);
			else if ( viz[ L[lg-1] ] < 0 )
				q = min(q, f[ L[lg-1] ][ L[lg] ]);
		}

		v = min(p, q);

		for ( int i = lg; i; --i )
			if ( viz[ L[i-1] ] >= 0 )
				f[ L[i] ][ L[i-1] ] += v;
			else
				f[ L[i-1] ][ L[i] ] -= v;
	}
}

void BF(int s)
{
    int p = 0, u = 0;
    memset(viz, 0, sizeof(viz));

    int x = 0;
    viz[s] = 1;
    C[p] = s;
    crit[s] = s;

    while ( p <= u )
    {
        x = C[p++];

        for ( int i = 1; i <= n; ++i )
            if ( !viz[i] && f[x][i] < a[x][i] && f[i][x] < a[i][x] )
                viz[i] = 1, crit[i] = s, C[++u] = i;
    }
}

int main()
{
	read();
	flux();

    BF(1);
    BF(n);

    int cnt = 0;
    int answ[maxm];

    for ( int i = 0; i < m; ++i )
        if ( crit[ mc[i].x ] && crit[ mc[i].y ] && crit[ mc[i].x ] != crit[ mc[i].y ] )
            //&& (f[ mc[i].x ][ mc[i].y ] == a[ mc[i].x ][ mc[i].y ])
            //|| (f[ mc[i].y ][ mc[i].x ] == a[ mc[i].y ][ mc[i].x ]) )
            answ[cnt++] = i+1;

    fprintf(out, "%d\n", cnt);
    for ( int i = 0; i < cnt; ++i )
        fprintf(out, "%d\n", answ[i]);

	return 0;
}