#include <bits/stdc++.h>
#define forsn(i, s, n) for (int i = int(s); i < int(n); i++)
#define forn(i, n) forsn(i, 0, n)
#define dforsn(i, s, n) for (int i = int(n) - 1; i >= int(s); i--)
#define dforn(i, n) dforsn(i, 0, n)
using namespace std;
using vi = vector<int>;
const int MAX_N = 2005;
const int MOD = 1000000007;
int memo1[MAX_N][MAX_N][2][2];
int memo2[MAX_N][MAX_N][2];
int dp(int n, int s, int t, bool inc) {
if (s > t) return dp(n, n - s + 1, n - t + 1, !inc);
if (n == 2) return inc;
if (s > 1) {
int &ret = memo1[n][s][inc][t == n];
if (ret != -1) return ret;
if (inc) {
ret = dp(n, s - 1, t, inc) - dp(n - 1, s - 1, t - 1, !inc);
if (ret < 0) ret += MOD;
} else {
ret = dp(n, s - 1, t, inc) + dp(n - 1, s - 1, t - 1, !inc);
if (ret >= MOD) ret -= MOD;
}
return ret;
}
if (!inc) return 0;
int &ret = memo2[n][t][inc];
if (ret != -1) return ret;
if (t < n) {
ret = dp(n, n - t + 1, n, true) + dp(n, n - t + 1, n, false);
if (ret >= MOD) ret -= MOD;
return ret;
}
ret = 0;
forsn(i, 2, n - 1) {
ret += dp(n - 1, i, t - 1, false);
if (ret >= MOD) ret -= MOD;
}
return ret;
}
int main() {
int n, s, t;
cin >> n >> s >> t;
memset(memo1, -1, sizeof memo1);
memset(memo2, -1, sizeof memo2);
int ret = dp(n, s, t, false) + dp(n, s, t, true);
if (ret >= MOD) ret -= MOD;
cout << ret << '\n';
return 0;
}
