#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
const int mod = 1000000007;
vector<int> groups;
vector<int> groupsize;
int get_root(int a) {
int t = a;
while (a != groups[a])
a = groups[a];
while (t != groups[t])
{
int p = groups[t];
groups[t] = a;
t = p;
}
return a;
}
bool group_merge(int a, int b) {
a = get_root(a);
b = get_root(b);
if (a == b)
return false;
if (groupsize[a] < groupsize[b]) {
swap(a, b);
}
groups[b] = a;
groupsize[a] += groupsize[b];
return true;
}
int main() {
int n, m;
scanf("%d%d", &n, &m);
long long ans = 1;
vector<pair<int, int>> dat;
vector<int> vertices;
for (int i = 0; i < m; i++) {
int a, b;
scanf("%d%d", &a, &b);
a--, b--;
dat.emplace_back(a, b);
vertices.push_back(a);
vertices.push_back(b);
}
sort(vertices.begin(), vertices.end());
vertices.erase(unique(vertices.begin(), vertices.end()), vertices.end());
groupsize.assign(vertices.size(), 1);
for (int i = 0; i < vertices.size(); i++) {
groups.push_back(i);
}
for (int i = 0; i < m; i++) {
int a = dat[i].first;
int b = dat[i].second;
a = lower_bound(vertices.begin(), vertices.end(), a) - vertices.begin();
b = lower_bound(vertices.begin(), vertices.end(), b) - vertices.begin();
if (!group_merge(a, b)) {
ans = 0;
}
}
if (m >= n)
ans = 0;
int c = n - m;
if (c >= 2) {
for (int i = 0; i < c - 2; i++) {
ans *= n;
ans %= mod;
}
for (int i = 0; i < vertices.size(); i++) {
if (i == groups[i]) {
ans *= groupsize[i];
ans %= mod;
}
}
}
printf("%lld\n", ans);
return 0;
}
