// ConsoleApplication1.cpp: определяет точку входа для консольного приложения.
//

#include "stdafx.h"
#include <iostream>

using namespace std;

int fact(int);
int fact_r(int);
int fact_s(int);
int fib_r(int);
int fib_ar(int);
int fib_arr(int);
int fib_arr_mem(int);
int sigma(int from, int to, int(*func)(int));

int main()
{
    char a;
    int n, x;
    cin >> x;
    cout << "";
    cin >> n;
    switch (x) {

        case 1:
        {
            cout << fact(n);
            break;
        }
        case 2:
        {
            cout << fact_s(n);
            break;
        }
        case 3:
        {
            cout << fib_r(n);
            break;
        }
        case 4:
        {
            cout << fib_ar(n);
            break;
        }
        case 5:
        {
            cout << fib_arr(n);
            break;
        }
        case 6:
        {
            cout << fib_arr_mem(n);
            break;
        }
        case 7:
        {
            cout << sigma(1, n, fact_r);
            break;
        }
    }

    cin >> a;
    return 0;
}

int fact(int n)
{
    int sum = 0;
    int f = 1;
    if (n < 0)
        return 0;
    for (int i = 1; i <= n; i++)
    {
        f = f * i;
        sum = sum + f;
    }
    return sum;
}

int fact_r(int n)
{
    if (n < 0)
        return 0;
    if (n <= 1)
        return 1;
    return n * fact_r(n-1);
}

int fact_s(int n)
{
    if (n < 0)
        return 0;
    if (n <= 1)
        return 1;
    return fact_s(n - 1) + fact_r(n);
}

int fib_r(int n)
{
    if (n <= 2 && n > 0)
        return 1;
    return fib_r(n - 1) + fib_r(n - 2);
}

int fib_ar(int n)
{
    int* ar = new int[n];
    ar[0] = 1;
    ar[1] = 1;
    for (int i = 2; i < n; i++)
    {
        ar[i] = ar[i - 1] + ar[i - 2];
    }
    return ar[n - 1];
}

int fib_arr(int n)
{
    int* ar = new int[n];
    for (int i = 0; i <= n; i++) {
        ar[i] = 0;
    }

    ar[0] = 1;
    for (int i = 0; i - 2 < n && i - 2 < n; i++)
    {
        ar[i + 1] += ar[i];
        ar[i + 2] += ar[i];
    }
    return ar[n - 1];
}

int fib_arr_mem(int n)
{
    static int* ar = new int[n];
    static int n_array;
    static int f;
    if (!f)
    {
        n_array = 2;
        for (int i = 0; i <= n; i++)
        {
            ar[i] = 0;
        }
        ar[1] = 1;
        ar[2] = 1;
        f = 1;
    }
    if (n <= n_array)
        return ar[n];
    ar[n] = fib_arr_mem(n - 1) + fib_arr_mem(n - 2);
    n_array = n > n_array ? n : n_array;
    return ar[n];
}

int sigma(int from, int to, int(*func)(int))
{
    int sum = 0;
    while (from <= to)
        sum += (*func)(from++);
    return sum;
}