#include <bits/stdc++.h>
using namespace std;
// #define int long long
#define eb emplace_back
#define mp make_pair
#define pb push_back
#define pp pop_back
#define endl '\n'
#define ff first
#define ss second
#define stop exit(0)
#define sz(x) (int)x.size()
#define pause system("pause")
#define all(x) (x).begin(), (x).end()
#define deb(x) cout << #x << "-" << x << endl
typedef char chr;
typedef string str;
typedef long long ll;
typedef vector<int> vii;
typedef pair<int, int> pii;
const long long INF = LLONG_MAX;
const int inf = INT_MAX;
const int mod = 998244353;
const int MOD = 1e9 + 7;
const int dx[] = {0, 0, -1, 1};
const int dy[] = {-1, 1, 0, 0};
const double PI = 2 * acos(0.0);
const int N = 2e3 + 5;
int n,cs,cf;
int fix[N];
int ans;
void rec(int rep, bool dir,int last) {
if (rep != n && fix[cf]) {
return;
}
if (rep == n) {
if (last == cf) ans++;
return;
}
if (dir) {
bool ok = 0;
for (int i = last+1; i <= n; i++) {
if (!fix[i]) ok = 1;
}
if (!ok) {
return;
}
for (int i = last+1; i <= n; i++) {
if (!fix[i]) {
fix[i] = 1;
rec(rep+1,!dir,i);
fix[i] = 0;
}
}
} else {
bool ok = 0;
for (int i = last-1; i >= 1; i--) {
if (!fix[i]) ok = 1;
}
if (!ok) {
return;
}
for (int i = last-1; i >= 1; i--) {
if (!fix[i]) {
fix[i] = 1;
rec(rep+1,!dir,i);
fix[i] = 0;
}
}
}
}
inline void test_case() {
cin >> n >> cs >> cf;
fix[cs] = 1;
rec(1,1,cs);
for (int i = 1; i <= n; i++) {
fix[i] = 0;
}
fix[cs] = 1;
rec(1,0,cs);
cout << ans << endl;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int T = 1;
// cin >> T;
while (T--) {
test_case();
}
return 0;
}
