#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int mod = 1e9 + 7;
int32_t main () {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int N, U, V;
cin >> N >> U >> V;
-- U;
-- V;
map<long long, int> memo;
function<void(long long, int, int )> func = [&](long long tmp, int ind, int dir) -> void {
if (ind == V) {
memo[tmp] = (tmp == 0);
return;
}
bool ch = (memo.find(tmp) == memo.end());
if (dir != 0) {
bool as = false;
for (int i = ind + 1;i < N;i ++) if ((tmp & (1LL << i)) > 0) {
as = true;
break;
}
if (!as) {
memo[tmp] = 0;
} else if (ch == true) {
for (int i = ind + 1;i < N;i ++) if ((tmp & (1LL << i)) > 0) {
func ((tmp ^ (1LL << i)), i, 0);
memo[tmp] = (memo[(tmp ^ (1LL << i))] + memo[tmp]) % mod;
}
}
}
if (dir != 1) {
bool as = false;
for (int i = ind - 1;i >= 0;i --) if ((tmp & (1LL << i)) > 0) {
as = true;
break;
}
if (!as) {
memo[tmp] = 0;
} else if (ch == true) {
for (int i = ind - 1;i >= 0;i --) if ((tmp & (1LL << i)) > 0) {
func ((tmp ^ (1LL << i)), i, 1);
memo[tmp] = (memo[(tmp ^ (1LL << i))] + memo[tmp]) % mod;
}
}
}
};
func (((1 << N) - 1) ^ (1 << U), U, -1);
// cout << (((1 << N) - 1) ^ (1 << U)) << "\n";
cout << memo[((1 << N) - 1) ^ (1 << U)] << "\n";
// for (auto v : memo) {
// cout << v.first << " " << v.second << "\n";
// }
}
