#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> dp;
int n, s, e;
const int mod = 1000000007;
int solve(const int i, const int j){
if(i == 1) {
if (j == 1) return 1;
return 0;
}
if(i < 0 || i > n) return 0;
if(j < 0 || j > n) return 0;
int &ans = dp[i][j];
if(ans != -1) return ans;
if(i == s || i == e) {
int p1 = solve(i - 1, j - 1); // new components
int p2 = solve(i - 1, j); // same component
return ans = (0LL + p1 + p2) % mod;
}
if(i > e) {
int p1 = solve(i - 1, j - 1) * (j - 2LL) % mod;
int p2 = solve(i - 1, j) * ((j - 2) * 2LL + 2) % mod;
int p3 = solve(i - 1, j + 1) * 1LL * j % mod;
return ans = (0LL + p1 + p2 + p3) % mod;
}
if(i > s) {
int p1 = solve(i - 1, j - 1) * 1LL * (j - 1) % mod; // new component
int p2 = solve(i - 1, j) * 1LL * ((j - 1) * 2 + 1) % mod; // same component
int p3 = solve(i - 1, j + 1) * 1LL * j % mod; // merge two components
return ans = (0LL + p1 + p2 + p3) % mod;
}
if(i < s) {
int p1 = solve(i - 1, j - 1) * 1LL * j % mod; // new component
int p2 = solve(i - 1, j) * 1LL * (2 * j) % mod; // same component
int p3 = solve(i - 1, j + 1) * 1LL * j % mod; // merge two components
return ans = (0LL + p1 + p2 + p3) % mod;
}
assert(false);
return 0;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
// freopen("kangaroo.in", "r", stdin);
// freopen("kangaroo.out", "w", stdout);
while(cin >> n >> s >> e) {
dp = vector<vector<int>> (n + 1, vector<int>(n + 1, -1));
if(s > e) swap(s, e);
cout << solve(n, n) << '\n';
}
return 0;
}
