#include <bits/stdc++.h>
using namespace std;

template<int MaxN, int MaxR, long long Mod>
struct StaticCombination {
    using value_type = long long;
    value_type table[MaxN+1][MaxR+1];

    constexpr StaticCombination() :table() {
        for (int n = 0; n < MaxN; ++n) {
            table[n][0] = 1;
            for (int r = 0; r <= n && r < MaxR; ++r)
                table[n + 1][r + 1] = (table[n][r + 1] + table[n][r]) % Mod;
        }
    }

    constexpr inline value_type operator()(int n, int r) const {
        return table[n][r];
    }
};

//constexpr StaticCombination<2500, 2500, 1000000007ll> sc;
StaticCombination<2500, 2500, 1000000007ll> sc;

int main(){
    cerr << sc(2500,2500) << endl;
    cout << 0 << endl;
    return 0;
}