#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <assert.h>

using namespace std;

int n, m;
int times = 0;
int colors = 0;
int bridges = 0;

vector< vector<int> > g;
vector<int> enter, ret, cnt;
vector<int> size;
vector<bool> used;
vector<int> color;


long long ans = 0;

void dfs(int v)
{
    size[v] = 1;
    for (size_t i = 0; i < g[v].size(); i++)
    {
        int u = g[v][i];
        if (size[u] == 0)
        {
            dfs(u);
            size[v] += size[u];
        }
    }
}

void paint(int v, int col)
{
    used[v] = true;
    color[v] = col;
    for (size_t i = 0; i < g[v].size(); i++)
    {
        int u = g[v][i];
        if (!used[u])
            paint(u, col);
    }
}

void search_bridge(int v, int p = -1)
{
    used[v] = true;
    enter[v] = ret[v] = times++;
    for (size_t i = 0; i < g[v].size(); i++)
    {
        int t = g[v][i];
        if (t == p) continue;
        if (used[t])
            ret[v] = min(ret[v], enter[t]);
        else
        {
            search_bridge(t, v);
            ret[v] = min(ret[v], ret[t]);
            if (ret[t] > enter[v])
            {
                bridges++;
                cnt.push_back(size[t]);
            }
        }
    }
};

int main()
{
    // freopen("edges.in", "r", stdin);
    // freopen("edges.out", "w", stdout);
    cin >> n >> m;
    assert(1 <= n && n <= 1e5);
    assert(0 <= m && m <= 2e5);
    g.resize(n);
    int x, y;
    set< pair<int, int> > q;
    for (int i = 0; i < m; i++)
    {
        cin >> x >> y;
        assert(1 <= x && x <= n);
        assert(1 <= y && y <= n);
        assert(x != y);
        pair<int, int> e = make_pair(min(x, y), max(x, y));
        assert(q.count(e) == 0);
        q.insert(e);
        g[x - 1].push_back(y - 1);
        g[y - 1].push_back(x - 1);
    }
    q.clear();
    used.resize(n, false);
    color.resize(n);
    size.resize(n);
    for (size_t i = 0; i < n; i++)
        if (!used[i])
        {
            paint(i, colors++);
            dfs(i);
        }
    if (colors > 2)
    {
        cout << "0\n";
        return 0;
    }
    enter.resize(n, 0);
    ret.resize(n, 0);
    used.assign(n, false);
    for (size_t i = 0; i < n; i++)
        if (!used[i]) search_bridge(i);
    if (colors == 2)
    {
        long long size1 = 0;
        long long size2 = 0;
        for (size_t i = 0; i < n; i++)
            if (color[i] == 1) size1++;
            else size2++;
        ans = size1 * size2;
        ans *= (m - bridges);
        cout << ans << endl;
        return 0;
    }
    if (colors == 1)
    {
        ans =  m - bridges;
        ans *= (long long)n * (long long)(n - 1) / 2 - m;
        for (size_t i = 0; i < cnt.size(); i++)
            ans += (long long)(n - cnt[i]) * cnt[i] - 1;
        cout << ans << endl;
        return 0;
    }
}