/* Problem URL: https://codeforces.com/edu/course/2/lesson/6/4/practice/contest/285069/problem/B */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m;
    cin >> n >> m;

    V<V<pair<int, int>>> graph(n);

    while (m--) {
        int a, b, c;
        cin >> a >> b >> c;

        graph[a - 1].emplace_back(b - 1, c);
    }

    vi parent(n);

    long double low = 0;
    long double high = 1e3;
    long double act = 0;
    long double eps = 1e-9;

    vi next(n, -1);

    long double inf = 1e18;

    while ((high - low) >= eps) {
        long double mid = (high + low) / 2;

        V<long double> memo(n, -inf);

        function<long double(int)> dfs = [&](int i) {
            long double &ans = memo[i];
            if (ans != -inf) {
                return ans;
            }

            if (i == n - 1) {
                ans = 0;
                return ans;
            }

            ans = inf;

            for (auto [j, c] : graph[i]) {
                // rmin(ans, dfs(j) + c - mid);
                long double tmp = dfs(j) + c - mid;
                if (tmp <= ans) {
                    next[i] = j;
                    ans = tmp;
                }
            }

            return ans;
        };

        long double tmp = dfs(0);

        if (tmp <= 0) {
            high = mid;
            act = mid;
            continue;
        }

        low = mid;
    }

    vi ans = {1};

    int now = next[0];

    while (now != n - 1) {
        ans.push_back(now + 1);
        now = next[now];
    }

    ans.push_back(n);

    cout << ans.size() - 1 << '\n' << ans;
}