#include<bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
long long memo[2001][2001];
long long dp(int i, int j, const int& n, const int& st, const int& ending) {
if (i == n) {
if (j == 1) return 1;
return 0;
}
if (memo[i][j] != -1) {
return memo[i][j];
}
long long res = 0;
long long r1 = 0;
long long r2 = 0;
if (i == st || i == ending) {
if (j >= 1)
r1 = dp(i + 1, j, n , st, ending);
r2 = dp(i + 1, j + 1, n ,st, ending);
} else {
if (j >= 2)
r1 = ((j - 1 + mod) * dp(i + 1, j - 1, n, st, ending))%mod;
int ed = (i>st) + (i>ending);
int tot = (j - ed <= 0)?1: j - ed;
r2 = (tot * dp(i + 1,j + 1, n, st, ending))%mod;
}
res = (r1 + r2)%mod;
memo[i][j] = res;
return res;
}
int main() {
int n, st, ending;
cin >> n >> st >> ending;
st--;
ending--;
memset(memo, -1, sizeof(memo));
cout << dp(0 ,0, n, st, ending) << endl;
}
