#include <bits/stdc++.h>
using namespace std;

signed main() {
#ifndef LOCAL
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
#else
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    int n, s, f;
    cin >> n >> s >> f;
    s--, f--;
    vector<int> p(n);
    iota(p.begin(), p.end(), 0);
    int cnt = 0;
    do {
        if (p.front() != s || p.back() != f) {
            continue;
        }
        bool ok = true;
        for (int i = 0; i + 2 < n; i++) {
            if (p[i] < p[i + 1]) {
                ok &= p[i + 1] > p[i + 2];
            } else {
                ok &= p[i + 1] < p[i + 2];
            }
        }
        cnt += ok;
    } while (next_permutation(p.begin(), p.end()));

    cout << cnt << '\n';
    return 0;
}