/* #ifndef ONLINE_JUDGE #include "AkbarKING.h" #else #define debug(...) #define debugArr(...) #define debugG(...) #endif */ #include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> #include <ext/pb_ds/hash_policy.hpp> #define int long long #define $AzH_TxdmN$ ios_base::sync_with_stdio(0);cin.tie(nullptr);cout.tie(nullptr); #pragma GCC target("sse,sse2,sse3,ssse3,popcnt,abm,mmx,tune=native") #pragma GCC optimize("Ofast") #pragma GCC optimize("no-stack-protector") #pragma GCC optimize("unroll-loops") #pragma GCC optimize("fast-math") ///* #define NaxcivanlilaraEkranKaydiAlmayaSonOnlardaInsanKimiKocureBilerlerVeSecmedeGCD100LeyeBilerler dp[1][1]; #define Aliyyiakbar dp[i][j] #define MirrehimM dp[0][0] #define Xanlar dp[i-1][j] #define Elay dp[i][j-1] #define Rufo dp[i-1][j-1] #define Yusif dp[i+1][j] #define Sayad dp[i][j+1] #define Sumuraz dp[i+1][j+1] #define Cebrayil dp[i+1][j-1] #define Riyad dp[n][m] #define Huseyn dp[n-1][m] #define Zako dp[n][m-1] #define Abdulla dp[n-1][m-1] #define Subhan dp[n+1][m] #define Sadiks dp[i+1][j-1] #define Khadija dp[i-1][j+1] ///*/ #define ep emplace_back #define pb push_back #define pii pair<int,int> #define all(v) v.begin(),v.end() #define rall(v) v.rbegin(),v.rend() using namespace std; using namespace __gnu_pbds; template <typename T> using __indexed_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; template <typename T> using __indexed_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>; mt19937_64 rng(chrono::steady_clock().now().time_since_epoch().count()); const int sz = 2e3 + 9; const int LOG = 63; const int MOD = 1e9 + 7; const int INF = 1e18; int dp[sz][sz]; int n, a, b; void solve() { cin >> n >> a >> b; MirrehimM = 1; for (int i = 1; i <= n; ++i) { for (int j = 1; j <= n; ++j) { if (i == a || i == b) { Aliyyiakbar = ((Xanlar + Rufo) % MOD + MOD) % MOD; } else { Aliyyiakbar = (((((((Khadija * j) % MOD + MOD) % MOD) + ((((Rufo * (j - (i > a) - (i > b))) % MOD) + MOD) % MOD) + MOD) % MOD) + MOD) % MOD + MOD) % MOD; } } } cout << dp[n][1] << '\n'; } signed main() { $AzH_TxdmN$ int t = 1; // cin >> t; while (t--) { solve(); } }