代碼:
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <cmath>
#include <string>
#include <vector>
#include <cstdio>
#include <cctype>
#include <cstring>
#include <sstream>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#pragma comment(linker,"/STACK:102400000,102400000")
using namespace std;
#define MAX 5005
#define MAXN 1000005
#define maxnode 105
#define sigma_size 30
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define lrt rt<<1
#define rrt rt<<1|1
#define middle int m=(r+l)>>1
#define LL long long
#define ull unsigned long long
#define mem(x,v) memset(x,v,sizeof(x))
#define lowbit(x) (x&-x)
#define pii pair<int,int>
#define bits(a) __builtin_popcount(a)
#define mk make_pair
#define limit 10000
//const int prime = 999983;
const int INF = 0x3f3f3f3f;
const LL INFF = 0x3f3f;
const double pi = acos(-1.0);
const double inf = 1e18;
const double eps = 1e-6;
const LL mod = 10007;
const ull mx = 133333331;
/*****************************************************/
inline void RI(int &x) {
char c;
while((c=getchar())<'0' || c>'9');
x=c-'0';
while((c=getchar())>='0' && c<='9') x=(x<<3)+(x<<1)+c-'0';
}
/*****************************************************/
ull dp[MAX];
ull dd[MAX];
void init(){
dp[1]=0;dd[1]=0;
dp[2]=1;dp[3]=1;dp[4]=3;
dd[2]=1;dd[3]=1;dd[4]=1;
for(int i=5;i<=5000;i++){
dp[i]=0;
dd[i]=0;
for(int j=2;j<=i-1;j++){
dp[i]+=dp[j]*dp[i-j+1];
dd[i]+=dp[j]*dp[i-j];
}
for(int j=2;j<=i-2;j++){
dp[i]+=dp[j]*dd[i+2-j];
}
}
}
int main(){
//freopen("in.txt","r",stdin);
init();
int n;
while(~scanf("%d",&n)){
printf("%llu\n",dp[n]);
}
return 0;
}