#include "bits/stdc++.h" using namespace std; #define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i)) #define rep(i,j) FOR(i,0,j) #define each(x,y) for(auto &(x):(y)) #define mp make_pair #define MT make_tuple #define all(x) (x).begin(),(x).end() #define debug(x) cout<<#x<<": "<<(x)<; using vi = vector; using vll = vector; template class ModInt { public: ModInt() :value(0) {} ModInt(long long val) :value((int)(val<0 ? MOD + val%MOD : val%MOD)) { } ModInt& operator+=(ModInt that) { value = value + that.value; if (value >= MOD)value -= MOD; return *this; } ModInt& operator-=(ModInt that) { value -= that.value; if (value<0)value += MOD; return *this; } ModInt& operator*=(ModInt that) { value = (int)((long long)value * that.value % MOD); return *this; } ModInt &operator/=(ModInt that) { return *this *= that.inverse(); } ModInt operator+(ModInt that) const { return ModInt(*this) += that; } ModInt operator-(ModInt that) const { return ModInt(*this) -= that; } ModInt operator*(ModInt that) const { return ModInt(*this) *= that; } ModInt operator/(ModInt that) const { return ModInt(*this) /= that; } ModInt pow(long long k) const { if (value == 0)return 0; ModInt n = *this, res = 1; while (k) { if (k & 1)res *= n; n *= n; k >>= 1; } return res; } ModInt inverse() const { long long a = value, b = MOD, u = 1, v = 0; while (b) { long long t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v); } return ModInt(u); } int toi() const { return value; } private: int value; }; typedef ModInt<1000000007> mint; ostream& operator<<(ostream& os, const mint& x) { os << x.toi(); return os; } mint dp[2001][2001]; int N; void calc() { for (int i = 2; i <= N-1; ++i) { int cur = 0; mint sm; for (int j = 1; j <= N; ++j) { while (cur - (i - 1) < j && cur<=N) { sm += dp[i - 1][cur++]; } dp[i][j] += sm; } } } int main(){ ios::sync_with_stdio(false); cin.tie(0); cin >> N; for (int i = 1; i <= N; ++i)for (int j = i; j <= N; ++j) { dp[1][j] += 1; } calc(); mint ans; rep(i, N + 1)ans += dp[N - 1][i]; MEM(dp, 0); for (int j = 1; j <= N; ++j) { dp[1][j] = 1; } calc(); ans -= dp[N - 1][N]; cout << ans << endl; }