Red Huang

//====================================================================||  
// Name        : Counting.cpp                                              ||  
// Date : 2013/7/20 下午1:51:45                                               ||  
// Author : GCA                                                       ||  
//                  6AE7EE02212D47DAD26C32C0FE829006                  ||  
//====================================================================||  
#include <iostream>  
#include <cstdio>  
#include <cstring>  
#include <algorithm>  
#include <cmath>  
#include <climits>  
#include <vector>  
#include <set>  
#include <map>  
#include <queue>  
#include <cctype>  
#include <utility>  
using namespace std;  
#ifdef ONLINE\_JUDGE  
#define ll "%lld"  
#else  
#define ll "%I64d"  
#endif  
typedef unsigned int uint;  
typedef long long int Int;  
#define Set(a,s) memset(a,s,sizeof(a))  
#define Write(w) freopen(w,"w",stdout)  
#define Read(r) freopen(r,"r",stdin)  
#define Pln() printf("\\n")  
#define I\_de(x,n)for(int i=0;i<n;i++)printf("%d ",x\[i\]);Pln()  
#define De(x)printf(#x"%d\\n",x)  
#define For(i,x)for(int i=0;i<x;i++)  
#define CON(x,y) x##y  
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\\  
    printf("%d ",dp\[htx\]\[hty\]);}Pln();}  
#define M 10011  
#define PII pair<int,int\>  
#define PB push\_back  
#define oo INT\_MAX  
#define Set\_oo 0x3f  
#define Is\_debug true  
#define debug(...) if(Is\_debug)printf("DEBUG: "),printf(\_\_VA\_ARGS\_\_)  
#define FOR(it,c) for(\_\_typeof((c).begin()) it=(c).begin();it!=(c).end();it++)  
#define eps 1e-6  
bool xdy(double x,double y){return x>y+eps;}  
bool xddy(double x,double y){return x>y-eps;}  
bool xcy(double x,double y){return x<y-eps;}  
bool xcdy(double x,double y){return x<y+eps;}  
int min3(int x,int y,int z){  
    int tmp=min(x,y);  
    return min(tmp,z);  
}  
int max3(int x,int y,int z){  
    int tmp=max(x,y);  
    return max(tmp,z);  
}  
class bignum{  
public:  
    Int n\[150\];  
    const static int maxn=150;  
    const static int base\=10000;  
    bignum(){  
        Set(n,0);  
    }  
    void clear(){  
        Set(n,0);  
    }  
    bignum add(Int x){  
        bignum ans;  
        Int c=0;  
        for(int i=0;i<maxn;i++){  
            Int tmp=n\[i\]+x+c;  
            x=0;  
            ans.n\[i\]=tmp%base;  
            c=tmp/base;  
        }  
        return ans;  
    }  
    bignum mul(int a){  
        bignum ans;  
        Int c=0;  
        for(int i=0;i<maxn;i++){  
            Int tmp=n\[i\]\*a+c;  
            ans.n\[i\]+=tmp%base;  
            c=tmp/base;  
            for(int j=i+1;j<maxn;j++){  
                Int tmp2=ans.n\[j\]+c;  
                ans.n\[j\]=tmp2%base;  
                c=tmp2/base;  
                if(!c)break;  
            }  
        }  
        return ans;  
    }  
    bignum operator+(bignum &d)const{  
        bignum ans;  
        Int c=0;  
        for(int i=0;i<maxn;i++){  
            Int tmp=n\[i\]+d.n\[i\]+c;  
            ans.n\[i\]=tmp%base;  
            c=tmp/base;  
        }  
        return ans;  
    }  
    bool operator!=(bignum &d)const{  
        for(int i=0;i<maxn;i++){  
            if(d.n\[i\]==n\[i\])return false;  
        }  
        return true;  
    }  
    void print(){  
        int i=maxn-1;  
        for(;i>0;i--)if(n\[i\]!=0)break;  
        printf("%lld",n\[i--\]);  
        for(;i>=0;i--){  
            printf("%04lld",n\[i\]);  
        }Pln();  
    }  
};  
int n;  
bignum cnt;  
bignum dp\[1005\];  
bignum minu;  
void pre(){  
    dp\[1\]=dp\[1\].add(2);  
    dp\[2\]=dp\[2\].add(5);  
    dp\[3\]=dp\[3\].add(13);  
    for(int i=4;i<1001;i++){  
        dp\[i\]=dp\[i-1\].mul(2)+dp\[i-2\]+dp\[i-3\];  
    }  
}  
  
int main() {  
    ios\_base::sync\_with\_stdio(0);  
    pre();  
    while(~scanf("%d",&n)){  
        dp\[n\].print();  
    }  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
}