#include <bits/stdc++.h>
#define pb push_back
using namespace std;

class OutParser {
private:
    FILE *fout;
    char *buff;
    int sp;

    void write_ch(char ch) {
        if (sp == 50000) {
            fwrite(buff, 1, 50000, fout);
            sp = 0;
            buff[sp++] = ch;
        } else {
            buff[sp++] = ch;
        }
    }


public:
    OutParser(const char* name) {
        fout = fopen(name, "w");
        buff = new char[50000]();
        sp = 0;
    }
    ~OutParser() {
        fwrite(buff, 1, sp, fout);
        fclose(fout);
    }

    OutParser& operator << (int vu32) {
        if (vu32 <= 9) {
            write_ch(vu32 + '0');
        } else {
            (*this) << (vu32 / 10);
            write_ch(vu32 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (long long vu64) {
        if (vu64 <= 9) {
            write_ch(vu64 + '0');
        } else {
            (*this) << (vu64 / 10);
            write_ch(vu64 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (char ch) {
        write_ch(ch);
        return *this;
    }
    OutParser& operator << (const char *ch) {
        while (*ch) {
            write_ch(*ch);
            ++ch;
        }
        return *this;
    }
};

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};

InParser fi("critice.in");
OutParser fo("critice.out");


const int NMAX = 1005;
const int INF = (1e9);

int n, m;
vector <int> G[NMAX];
int C[NMAX][NMAX], F[NMAX][NMAX];
int p[NMAX];
bool viz[NMAX];
queue <int> Q;
vector <int> rez, rez2;
pair <int, int> much[10005];
bool drum[2][1005];

void dfsVerificare(int nod, int sef)
{
   drum[sef][nod] = 1;
   viz[nod] = 1;
   for (auto v: G[nod])
   {
      if (!viz[v] && F[nod][v] != C[nod][v] && F[v][nod] != C[v][nod])
      {
         dfsVerificare(v, sef);
      }
   }
}

int bfs()
{
    memset(viz, 0, sizeof(viz));
    //memset(p, 0, sizeof(p));

    while (!Q.empty())
      Q.pop();

    Q.push(1);
    viz[1] = 1;

    while (!Q.empty())
    {
        int curr = Q.front();
        Q.pop();

        if (curr == n)
         continue;

        for (auto v: G[curr])
        {
            if (F[curr][v] == C[curr][v] || viz[v])
                continue;

            Q.push(v);
            viz[v] = 1;
            p[v] = curr;
        }
    }
    return viz[n];
}

int main()
{
    fi >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        int u, v, c;
        fi >> u >> v >> c;
        G[u].pb(v);
        G[v].pb(u);
        C[u][v] = C[v][u] = c;
        much[i] = {u, v};
    }

    while (bfs())
        for (auto v: G[n])
        {
            if (F[v][n] == C[v][n] || !viz[v])
                continue;

            p[n] = v;

            int minim = INF, poz = -1;
            for (int nod = n; nod != 1 && minim > 0; nod = p[nod])
               minim = min(minim, C[p[nod]][nod] - F[p[nod]][nod]);

            if (minim == 0)
               continue;

            for (int nod = n; nod != 1; nod = p[nod])
            {
                F[p[nod]][nod] += minim;
                F[nod][p[nod]] -= minim;
            }
        }

    for (int i = 1; i <= m; i++)
    {
       int u = much[i].first, v = much[i].second;
       if (F[u][v] == C[u][v] || F[v][u] == C[v][u])
          rez.pb(i);
    }

    memset(viz, 0, sizeof(viz));
    dfsVerificare(1, 0);
    memset(viz, 0, sizeof(viz));
    dfsVerificare(n, 1);

    for (auto x: rez)
    {
       if ((drum[0][much[x].first] && drum[1][much[x].second])
          || (drum[1][much[x].first] && drum[0][much[x].second]))
          rez2.pb(x);
    }

    int xx = rez2.size();
    fo << xx << "\n";
    for (auto x: rez2)
        fo << x << "\n";

    return 0;
}