hdu_1023

// hdu 1023

// number theory - catalan number

// Jan.26 2015



#include <cstdio>

#include <cstring>

#include <algorithm>



#define MAXN 60



struct rev

{

    int num[MAXN];

    int l;

    // when the struct is constructed 

    // it's l value must be 1

    // ---- it's l must be 1 

    // ---- the num is 0 

    rev(int _l = 1)

    {

        memset(num, 0, sizeof(num));

        l = _l;

    }

}ca[101];



// two big number plus

rev add(rev a, rev b)

{

    rev s;

    s.l = std::max(a.l, b.l);

    int carry = 0;

    for(int i = 1; i <= s.l; ++i){

        int t = carry + a.num[i] + b.num[i];

        carry = t / 10;

        s.num[i] = t % 10;

    }

    if(carry){

        ++s.l;

        s.num[s.l] = 1;

    }

    return s;

}



// big number multiply big number

rev multiply(rev a, rev b)

{

    rev s;

    memset(s.num, 0, sizeof(s.num));

    s.l = 1;

    s.num[1] = 0;

    for(int i = 1; i <= a.l; ++i){

        rev temp;



        // Every digit of a should do a multiplication to b

        // and the i-th digit of a should have i-1 zero before the first zero-none digit 

        // for instance .

        // 45 * 123

        // the first digit of a is 5

        // 5 * 123 = 615 

        // 615 should puls no zero before

        // the second digit of b is 4

        // 4 * 123 = 492

        // but 492 should have 1 zero before 2

        // so the product of the multiplication is 4920

        // the result of 45*123 is 4920 + 615 =5535

        for(int pre_zero = 1; pre_zero < i; ++pre_zero)

            temp.num[pre_zero] = 0;

        temp.l = i-1;



        int multiplier_int = a.num[i];

        int carry = 0;

        for(int j = 1; j <= b.l; ++j){

            int t = multiplier_int * b.num[j] + carry;

            carry = t / 10;

            temp.num[++temp.l] = t % 10;

        }



        if(carry){

            ++temp.l;

            temp.num[temp.l] = carry;

        }

        s = add(s, temp);

    }

    return s;

}



void pre_do()

{

    memset(ca, 0, sizeof(ca));

    ca[0].num[1] = 1; ca[0].l = 1;

    ca[1].num[1] = 1; ca[1].l = 1;

    for(int i = 2; i <= 100; ++i){

        ca[i].num[1] = 0; ca[i].l = 1;

        rev temp;

        for(int j = 0; j < i; ++j){

            temp = multiply(ca[j], ca[i-j-1]);

            ca[i] = add(ca[i], temp);

        }



    }

}





int main(int argc, char const *argv[])

{

    pre_do();

    int n;

    while(~scanf("%d", &n)){

        for(int i = ca[n].l; i >= 1; --i)

            printf("%d", ca[n].num[i]);

        printf("\n");

    }

    // for(int i = 0; i <= 100; ++i){

    //     for(int j = ca[i].l; j >= 1; --j)

    //         printf("%d", ca[i].num[j]);

    //     printf("\n");

    // }

    return 0;

}