#include #include using namespace std; namespace std{ template inline void hash_combine(size_t& seed, T const& v){ seed ^= hash()(v) + 0x9e3779b9 + (seed<<6) + (seed>>2); } template inline size_t hash_range(It first, It last){ size_t seed=0; hash_range(seed,first,last); return seed; } template inline void hash_range(size_t& seed, It first, It last){ for(;first!=last;++first)hash_combine(seed, *first); } template class hash>{ public: size_t operator()(pair const &p) const{ size_t seed=0; hash_combine(seed,p.first); hash_combine(seed,p.second); return seed; } }; } unordered_map,int>,int>memo; int dfs(int k,int p,int d){ if(k<0||p<0)return 0; if(d==0)return 1; auto x=make_pair(make_pair(k,p),d); if(memo.find(x)==memo.end()){ memo[x]=(dfs(k-1,1,d-1)+dfs(2,p-1,d-1))%1000000007; } return memo[x]; } int main(){ int n; scanf("%d",&n); printf("%d\n",dfs(2,0,n)); }