Problem: Little Chris is participating in a graph cutting contest. He's a pro. The time has come to test his skills to the fullest.

Chris is given a simple undirected connected graph with n vertices (numbered from 1 to n) and m edges. The problem is to cut it into edge-distinct paths of length 2. Formally, Chris has to partition all edges of the graph into pairs in such a way that the edges in a single pair are adjacent and each edge must be contained in exactly one pair.

For example, the figure shows a way Chris can cut a graph. The first sample test contains the description of this graph.

<image>

You are given a chance to compete with Chris. Find a way to cut the given graph or determine that it is impossible!

Input

The first line of input contains two space-separated integers n and m (1 ≤ n, m ≤ 105), the number of vertices and the number of edges in the graph. The next m lines contain the description of the graph's edges. The i-th line contains two space-separated integers ai and bi (1 ≤ ai, bi ≤ n; ai ≠ bi), the numbers of the vertices connected by the i-th edge. It is guaranteed that the given graph is simple (without self-loops and multi-edges) and connected.

Note: since the size of the input and output could be very large, don't use slow output techniques in your language. For example, do not use input and output streams (cin, cout) in C++.

Output

If it is possible to cut the given graph into edge-distinct paths of length 2, output <image> lines. In the i-th line print three space-separated integers xi, yi and zi, the description of the i-th path. The graph should contain this path, i.e., the graph should contain edges (xi, yi) and (yi, zi). Each edge should appear in exactly one path of length 2. If there are multiple solutions, output any of them.

If it is impossible to cut the given graph, print "No solution" (without quotes).

Examples

Input

8 12
1 2
2 3
3 4
4 1
1 3
2 4
3 5
3 6
5 6
6 7
6 8
7 8


Output

1 2 4
1 3 2
1 4 3
5 3 6
5 6 8
6 7 8

Input

3 3
1 2
2 3
3 1


Output

No solution


Input

3 2
1 2
2 3


Output

1 2 3

Solution (in JAVA):

Solution:
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.io.IOException;
import java.util.ArrayList;
import java.io.UncheckedIOException;
import java.util.List;
import java.io.Closeable;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) throws Exception {
        Thread thread = new Thread(null, new TaskAdapter(), "", 1 << 29);
        thread.start();
        thread.join();
    }

    static class TaskAdapter implements Runnable {
        @Override
        public void run() {
            InputStream inputStream = System.in;
            OutputStream outputStream = System.out;
            FastInput in = new FastInput(inputStream);
            FastOutput out = new FastOutput(outputStream);
            CGraphCutting solver = new CGraphCutting();
            solver.solve(1, in, out);
            out.close();
        }
    }

    static class CGraphCutting {
        public void solve(int testNumber, FastInput in, FastOutput out) {
            int n = in.ri();
            int m = in.ri();
            Node[] nodes = new Node[n];
            for (int i = 0; i < n; i++) {
                nodes[i] = new Node();
                nodes[i].id = i;
            }
            DSU dsu = new DSU(n);
            dsu.init();
            Edge[] edges = new Edge[m];
            for (int i = 0; i < m; i++) {
                edges[i] = new Edge(nodes[in.ri() - 1], nodes[in.ri() - 1]);
                if (dsu.find(edges[i].a.id) != dsu.find(edges[i].b.id)) {
                    dsu.merge(edges[i].a.id, edges[i].b.id);
                    edges[i].a.adj.add(edges[i]);
                    edges[i].b.adj.add(edges[i]);
                }
            }

            for (int i = 0; i < n; i++) {
                if (dsu.find(i) == i) {
                    dfs(nodes[i], null);
                    if (nodes[i].deg == 1) {
                        out.println("No solution");
                        return;
                    }
                }
            }

            Edge[] carry = new Edge[n];
            for (Edge e : edges) {
                Node bind = e.to;
                if (carry[bind.id] != null) {
                    out.append(carry[bind.id].other(bind).id + 1).append(' ')
                            .append(bind.id + 1).append(' ')
                            .append(e.other(bind).id + 1).println();
                    carry[bind.id] = null;
                } else {
                    carry[bind.id] = e;
                }
            }
        }

        public void dfs(Node root, Edge p) {
            for (Edge e : root.adj) {
                Node node = e.other(root);
                if (e == p) {
                    continue;
                }
                dfs(node, e);
            }
            if (root.deg == 1 && p != null) {
                p.inv();
            }
        }

    }

    static class FastOutput implements AutoCloseable, Closeable, Appendable {
        private static final int THRESHOLD = 32 << 10;
        private final Writer os;
        private StringBuilder cache = new StringBuilder(THRESHOLD * 2);

        public FastOutput append(CharSequence csq) {
            cache.append(csq);
            return this;
        }

        public FastOutput append(CharSequence csq, int start, int end) {
            cache.append(csq, start, end);
            return this;
        }

        private void afterWrite() {
            if (cache.length() < THRESHOLD) {
                return;
            }
            flush();
        }

        public FastOutput(Writer os) {
            this.os = os;
        }

        public FastOutput(OutputStream os) {
            this(new OutputStreamWriter(os));
        }

        public FastOutput append(char c) {
            cache.append(c);
            afterWrite();
            return this;
        }

        public FastOutput append(int c) {
            cache.append(c);
            afterWrite();
            return this;
        }

        public FastOutput append(String c) {
            cache.append(c);
            afterWrite();
            return this;
        }

        public FastOutput println(String c) {
            return append(c).println();
        }

        public FastOutput println() {
            return append('\n');
        }

        public FastOutput flush() {
            try {
//            boolean success = false;
//            if (stringBuilderValueField != null) {
//                try {
//                    char[] value = (char[]) stringBuilderValueField.get(cache);
//                    os.write(value, 0, cache.length());
//                    success = true;
//                } catch (Exception e) {
//                }
//            }
//            if (!success) {
                os.append(cache);
//            }
                os.flush();
                cache.setLength(0);
            } catch (IOException e) {
                throw new UncheckedIOException(e);
            }
            return this;
        }

        public void close() {
            flush();
            try {
                os.close();
            } catch (IOException e) {
                throw new UncheckedIOException(e);
            }
        }

        public String toString() {
            return cache.toString();
        }

    }

    static class Node {
        int id;
        int deg;
        List<Edge> adj = new ArrayList<>();

    }

    static class DSU {
        protected int[] p;
        public int[] size;
        protected int n;

        public DSU(int n) {
            p = new int[n];
            size = new int[n];
        }

        public void init() {
            init(p.length);
        }

        public void init(int n) {
            this.n = n;
            for (int i = 0; i < n; i++) {
                p[i] = i;
                size[i] = 1;
            }
        }

        public final int find(int a) {
            if (p[a] == p[p[a]]) {
                return p[a];
            }
            find(p[a]);
            preAccess(a);
            return p[a] = p[p[a]];
        }

        protected void preAccess(int a) {

        }

        protected void preMerge(int a, int b) {
            size[a] += size[b];
        }

        public final void merge(int a, int b) {
            a = find(a);
            b = find(b);
            if (a == b) {
                return;
            }

            if (size[a] < size[b]) {
                int tmp = a;
                a = b;
                b = tmp;
            }
            preMerge(a, b);
            p[b] = a;
        }

        public String toString() {
            return Arrays.toString(Arrays.copyOf(p, n));
        }

    }

    static class Edge {
        Node a;
        Node b;
        Node to;

        public Edge(Node a, Node b) {
            this.a = a;
            this.b = b;
            to = a;
            to.deg ^= 1;
        }

        Node other(Node x) {
            return x == a ? b : a;
        }

        void inv() {
            to.deg ^= 1;
            to = other(to);
            to.deg ^= 1;
        }

    }

    static class FastInput {
        private final InputStream is;
        private byte[] buf = new byte[1 << 13];
        private int bufLen;
        private int bufOffset;
        private int next;

        public FastInput(InputStream is) {
            this.is = is;
        }

        private int read() {
            while (bufLen == bufOffset) {
                bufOffset = 0;
                try {
                    bufLen = is.read(buf);
                } catch (IOException e) {
                    bufLen = -1;
                }
                if (bufLen == -1) {
                    return -1;
                }
            }
            return buf[bufOffset++];
        }

        public void skipBlank() {
            while (next >= 0 && next <= 32) {
                next = read();
            }
        }

        public int ri() {
            return readInt();
        }

        public int readInt() {
            int sign = 1;

            skipBlank();
            if (next == '+' || next == '-') {
                sign = next == '+' ? 1 : -1;
                next = read();
            }

            int val = 0;
            if (sign == 1) {
                while (next >= '0' && next <= '9') {
                    val = val * 10 + next - '0';
                    next = read();
                }
            } else {
                while (next >= '0' && next <= '9') {
                    val = val * 10 - next + '0';
                    next = read();
                }
            }

            return val;
        }

    }
}