#include <iostream>
#include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <sstream>
#include <algorithm>
#include <functional>
#include <limits.h>
#include <bitset>

#include <tuple>
#include <unordered_map>

#define mp make_pair
#define mt make_tuple
#define pb push_back
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;

const int INF = 1 << 29;
const double EPS = 1e-9;

const int dx[] = {1, 0, -1, 0}, dy[] = {0, -1, 0, 1};
int N;
ll comb[55][55];

int main() {
  cin >> N;
  for (int i = 0; i <= 50; i++) {
    comb[i][0] = 1;
  }
  for (int i = 1; i <= 50; i++) {
  	comb[i][i] = 1;
    for (int j = 1; j < i; j++) {
      comb[i][j] = comb[i - 1][j] + comb[i - 1][j - 1];
    }
  }
  ll sum = 0;
  for (int i = 0; i <= 25; i++) {
    for (int j = 0; j <= 50; j++) {
      if (2 * i + j == N) {
        sum += comb[i + j][i];
      }
    }
  }
  cout << sum << endl;
  return 0;
}