// compile: make data
// run: time ./data < data.in
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#ifdef LOCAL
#include <debug/codeforces.h>
#define debug(x...) _debug_print(#x, x);
#define Debug(x...) _debug_print_format(#x, x);
#else
#define debug(x...)
#define Debug(x...)
#endif
template<typename...Args> void print_(Args...args){((cout<<args<<" "),...)<<endl;}
#define VI vector<int>
#define VII vector<vector<int>>
#define VIII vector<vector<vector<int>>>
#define rep(i,a,b) for(int i=(a);i<(int)(b);++i)
#define sz(v) ((int)(v).size())
#define print(...) print_(__VA_ARGS__);
#define FIND(a, x) ((find(a.begin(),a.end(),(x))!=a.end())?1:0)
#define cmin(x,...) x=min({(x), __VA_ARGS__})
#define cmax(x,...) x=max({(x), __VA_ARGS__})
#define INTMAX (int)(9223372036854775807)
#define INF (int)(1152921504606846976)
#define double long double
#define int long long
#define MAXN 200010
#define P 1000000007
 
int n, m;
// int dp[20][1<<20];
int e[20][400], cnt[20];
 
// int dfs(int u, int vis) {
//     if (~dp[u][vis]) return dp[u][vis];
//     if (vis == (1<<n)-1 && u == n-1) return dp[u][vis] = 1;
//     dp[u][vis] = 0;
//     rep(i, 0, cnt[u]) {
//         if (vis & (1<<e[u][i])) continue;
//         dp[u][vis] = (dp[u][vis] + dfs(e[u][i], vis | (1<<e[u][i]))) % P;
//     }
//     return dp[u][vis];
// }

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
 
    cin >> n >> m;
    rep(i, 0, m) {
        int u, v; cin >> u >> v; --u, --v;
        e[u][cnt[u]++] = v;
    }
    vector<vector<int>> dp(n, vector<int>(1<<n, 0));
    dp[0][1] = 1;
    rep(vis, 0, (1<<n)-1) {
        rep(u, 0, n) {
            if (!dp[u][vis] || !(vis & (1<<u))) continue;
            rep(i, 0, cnt[u]) {
                int v = e[u][i];
                if (vis & (1<<v)) continue;
                dp[v][vis | (1<<v)] = (dp[v][vis | (1<<v)] + dp[u][vis]) % P;
            }
        }
    }
    cout << dp[n-1][(1<<n)-1] << endl;
    // cout << dp[0][1] << endl;
 
    return 0;
}