#include<bits/stdc++.h>
#define ll long long
#define MaxN 2005
#define Mod 1000000007
using namespace std;
int n, s, t;
ll f[MaxN][MaxN];
ll multi(ll a, ll b) {
a %= Mod; b %= Mod;
return (a*b) % Mod;
}
ll dp(int i, int j) {
if (j < 0) return 0LL;
if (i == 1) return (j == 1);
if (f[i][j] != -1LL) return f[i][j];
ll res = 0LL;
if (i == s || i == t) {
res = (res + multi(dp(i-1, j-1), 1)) % Mod; // =))
res = (res + dp(i-1, j)) % Mod;
}
else {
if (i < s && i < t) res = (res + multi(dp(i-1, j-1), j)) % Mod;
else if (i < s || i < t) res = (res + multi(dp(i-1, j-1), j-1)) % Mod;
else res = (res + multi(dp(i-1, j-1), j-2)) % Mod;
res = (res + multi(dp(i-1, j+1), j)) % Mod;
}
f[i][j] = res;
return res;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> s >> t;
for(int i = 1; i <= n; ++i) {
for(int j = 1; j <= n; ++j) f[i][j] = -1LL;
}
cout << dp(n, 1) << "\n";
return 0;
}
