#include <iostream>
#include <queue>
#include <list>

using namespace std;

static int A[100][100];

struct route_t {
	int src, dst, cost;
};

bool operator <(const route_t &r1, const route_t &r2)
{
	return r1.cost > r2.cost;
}

int search(int src, int dst, int n, int p[])
{
	static int d[100];

	for(int i = 0; i < n; i++) {
		p[i] = -1;
		d[i] = -1;
	}

	priority_queue<route_t> q;
	route_t r;

	int pos = src;
	d[src] = 0;

	while(true) {
		for(int i = 0; i < n; i++) {
			if(A[pos][i] > 0 && d[i] < 0 && !(pos == src && i == dst)) {
				r.src  = pos;
				r.dst  = i;
				r.cost = d[pos] + A[pos][i];
				q.push(r);
			}
		}


		while(true) {
			if(q.empty()) return -1;
			r = q.top();
			q.pop();
			if(d[r.dst] < 0) break;
		}

		// cout << src + 1 << "," << dst + 1 << ": " << r.src + 1 << " -> " << r.dst + 1 << " (" << r.cost << ")" << endl;
		p[r.dst] = r.src;
		if(r.dst == dst) return r.cost;
		d[r.dst] = r.cost;
		pos = r.dst;
	}
}

int main(void)
{
	int n, m;
	while(cin >> n >> m) {
		if(n == -1) break;

		for(int i = 0; i < n; i++) {
			for(int j = 0; j < n; j++) {
				A[i][j] = -1;
			}
		}

		for(int i = 0; i < m; i++) {
			int s, t, c;
			cin >> s >> t >> c;
			--s; --t;
			if(A[s][t] == -1 || A[s][t] > c) {
				A[s][t] = A[t][s] = c;
			}
		}

		list<int> min_route;
		int min_len = -1;

		for(int i = 0; i < n; i++) {
			for(int j = i + 1; j < n; j++) {
				if(A[i][j] < 0 || (min_len >= 0 && A[i][j] >= min_len)) {
					continue;
				}

				static int p[100];
				int len = search(i, j, n, p);
				if(len < 0) continue;

				len += A[i][j];
				if(min_len < 0 || min_len > len) {
					min_len = len;
					int pos = j;

					min_route.clear();

					while(true) {
						min_route.push_back(pos + 1);
						if(pos == i) break;
						pos = p[pos];
					}
				}
			}
		}

		if(min_len < 0) {
			cout << "No solution." << endl;
		}
		else {
			while(true) {
				cout << min_route.back();
				min_route.pop_back();
				if(min_route.empty()) break;
				cout << " ";
			}

			cout << endl;
		}
	}

	return 0;
}