/* Problem URL: https://cses.fi/problemset/task/1690 */
 
#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;
 
    vvi graph(n);
    while (m--) {
        int a, b;
        cin >> a >> b;
 
        graph[a - 1].push_back(b - 1);
    }
 
    const ll mod = 1e9 + 7;
 
    vvl memo(n, vl(1 << n, -1));
 
    function<ll(int, ll)> dp = [&](int i, ll mask) -> ll {
        if (i == n - 1) {
            return mask == 0;
        }
 
        ll &ans = memo[i][mask];
        if (ans != -1) {
            return ans;
        }
 
        ans = 0;
 
        repv(j, graph[i]) {
            if (mask & (1 << j)) {
                ans += dp(j, mask ^ (1 << j));
                ans %= mod;
            }
        }
 
        return ans;
    };
 
    cout << dp(0, ((1 << n) - 1) ^ 1) << '\n';
}