#include <bits/stdc++.h>

using namespace std;

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;
	}
};

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;
    }
};

InParser in("critice.in");
OutParser out("critice.out");
int n, m, ok, ans;
vector<pair<int, int>> v[1005];
pair<int, int> muc[20005];
pair<int, int> viz[1005];
int viz2[1005];
int INF = (1 << 30);

void bfs(int cmin)
{
    viz[1] = {-1, -1};
    queue<int> q;
    q.push(1);

    while(!q.empty())
    {
        int nod = q.front();
        q.pop();

        if(nod == n)
        {
            break;
        }

        for(auto it: v[nod])
        {
            if(viz[it.first].first == 0 && muc[it.second].second - muc[it.second].first >= cmin)
            {
                viz[it.first] = {nod, it.second};
                q.push(it.first);
            }
        }
    }

    if(viz[n].first == 0)
    {
        return;
    }

    ok = 1;
    int nod = n;
    int flux = INF;

    while(viz[nod].first != -1)
    {
        flux = min(flux, muc[viz[nod].second].second - muc[viz[nod].second].first);

        nod = viz[nod].first;
    }

    nod = n;
    while(viz[nod].first != -1)
    {
        if(viz[nod].second <= m)
        {
            muc[viz[nod].second].first += flux;
            muc[viz[nod].second + m].first -= flux;
        }
        else
        {
            muc[viz[nod].second].first += flux;
            muc[viz[nod].second - m].first -= flux;
        }

        nod = viz[nod].first;
    }

}

void dfs2(int nod)
{
    viz2[nod] = 1;

    for(auto it: v[nod])
    {
        if(viz2[it.first] == 0 && muc[it.second].second - muc[it.second].first > 0)
        {
            dfs2(it.first);
        }
    }
}

int main()
{
    in>>n>>m;

    int x, y, z;
    int cmax = 0;
    for(int i = 1; i<=m; i++)
    {
        in>>x>>y>>z;

        v[x].push_back({y, i});
        muc[i] = {0, z};

        v[y].push_back({x, i + m});
        muc[i + m] = {0, z};

        cmax += 2 * z;
    }

    for(int i = cmax; i>=1; i /= 2)
    {
        ok = 1;
        while(ok == 1)
        {
            ok = 0;

            for(int j = 1; j<=n; j++)
            {
                viz[j] = {0, 0};
            }

            bfs(i);
        }
    }

    dfs2(1);

    for(int i = 1; i<=n; i++)
    {
        if(viz2[i] == 1)
        {
            for(auto it: v[i])
            {
                if(viz2[it.first] == 0)
                {
                    ans++;
                }
            }
        }
    }

    out<<ans<<'\n';
    for(int i = 1; i<=n; i++)
    {
        if(viz2[i] == 1)
        {
            for(auto it: v[i])
            {
                if(viz2[it.first] == 0)
                {
                    if(it.second <= m)
                    {
                        out<<it.second<<'\n';
                    }
                    else
                    {
                        out<<it.second - m<<'\n';
                    }
                }
            }
        }
    }

    return 0;
}