#include <stdio.h>
#include <stdlib.h>

long long factorial(int n)
{
	long long product = 1;
	while(n>1) product*=n--;
	return product;
}

long long nchoosek(int n, int k)
{
	return factorial(n) / (factorial(k) * factorial(n-k));
}

long long bell(int n)
{
	if(!n || !n--) return 1;
	long long sum = 0;
	for(int k = 0; k <= n; k++) sum+=bell(k)*nchoosek(n, k);
	return sum;
}

int main(int argc, char **argv)
{
	int i;
	//printf("Bell-Nr.: ");
	//scanf("%i", &i);
	i=atoi(argv[1]);
	printf("%lld\n", bell(i));	
	return 0;
}