#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
int N, cs, cf;
vector<vector<vector<int>>> dp;
int solve(int current, int prev, int mask) {
if (mask == (1 << N) - 1) {
return current == cf ? 1 : 0;
}
int &res = dp[current][prev][mask];
if (res != -1) return res;
res = 0;
for (int next = 0; next < N; ++next) {
if (mask & (1 << next)) continue;
if ((prev < current && next < current) || (prev > current && next > current)) {
res = (res + solve(next, current, mask | (1 << next))) % MOD;
}
}
return res;
}
int main() {
cin >> N >> cs >> cf;
cs--; cf--;
if (N > 20) {
return 0;
}
dp.assign(N, vector<vector<int>>(N, vector<int>(1 << N, -1)));
int ans = 0;
for (int next = 0; next < N; ++next) {
if (next == cs) continue;
ans = (ans + solve(next, cs, (1 << cs) | (1 << next))) % MOD;
}
cout << ans << "\n";
return 0;
}
