#include<bits/stdc++.h>
#define int long long

using namespace std;
const int maxn=1e7+5e6;
const int mod=1e9+7;
int jc[maxn],inv[maxn],n;
int mp[maxn];
struct hash_map{
	bool operator()(const pair<int,int>& p) const{
		return p.first+mp[p.second]*maxn;
	}
};
unordered_map<pair<int,int>,int,hash_map>dp;


int C(int n,int m){
	return jc[n]*inv[n-m]%mod*inv[m]%mod;
}
int ksm(int x,int p,int mod){
	int ans=1;
	while(p){
		if(p&1) ans=ans*x%mod;
		x=x*x%mod;
		p>>=1;
	}
	return ans;
}
int dfs(int x,int y){
	if(x==0) return 0;
	pair<int,int>t=make_pair(x,y);
	if(dp.find(t)!=t.end()) return dp[t];
	int r=min(2*x,n-y);
	int z=min(2*y,n-y);
	int sum=n-y;
	int mn=max(0LL,r+z-sum);
	int mx=min(r,z);
	int ans=1;
	int fm=ksm(C(n-y,z),mod-2,mod);
	for(int i=mn;i<=mx;i++){
		ans+=C(r,i)*C(n-y-r,z-i)%mod*dfs(r-i,z+y)%mod*fm%mod;
		ans%=mod;
	}
	return dp[t]=ans;
}
void init(){
	jc[0]=inv[0]=1;
	for(int i=1;i<maxn;i++) jc[i]=i*jc[i-1]%mod;
	inv[maxn-1]=ksm(jc[maxn-1],mod-2,mod);
	for(int i=maxn-2;i>=1;i--){
		inv[i]=(i+1)*inv[i+1]%mod;
	}
	mp[1]=0;
	int base=3;
	for(int i=1;;i++){
		if(base>=n){
			mp[n]=i;
			break;
		}
		mp[base]=i;
		//cout<<base<<" "<<mp[base]<<endl;
		base*=3;
		
	}
}
signed main(){
	//memset(dp,-1,sizeof(dp));
	cin>>n;
	init();
	
	int base=1;
	
	cout<<dfs(1,1)<<endl;
	return 0;
} 

answer.code: In function ‘long long int dfs(long long int, long long int)’:
answer.code:32:26: error: ‘struct std::pair<long long int, long long int>’ has no member named ‘end’
   32 |         if(dp.find(t)!=t.end()) return dp[t];
      |                          ^~~