#include <bits/stdc++.h>
using namespace std;
//#define DEBUG
void setIO(const string &name) {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin.exceptions(istream::failbit);
#ifdef LOCAL
freopen((name + ".in").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
freopen((name + ".out").c_str(), "w", stderr);
#endif
}
const int inf = 0x3f3f3f3f, mod = 1e9 + 7, maxn = 2005;
const long long INFL = 0x3f3f3f3f3f3f3f3f;
long long dp[maxn][maxn];
int main() {
setIO("1");
int n, start, end;
cin >> n >> start >> end;
dp[1][1] = 1;
for (int i = 2; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
long long &cur = dp[i][j];
if (i == start || i == end) {
cur = (dp[i - 1][j] + dp[i - 1][j - 1]) % mod;
} else {
cur += j * dp[i - 1][j + 1];
cur %= mod;
cur += (j - (i > start) - (i > end)) * dp[i - 1][j - 1];
cur %= mod;
}
}
}
cout << dp[n][1] << "\n";
return 0;
}
