#include<stdio.h>
int a[5005][1005];
int main()
{
	int n;
	int m = 0;
	scanf("%d", &n);
	a[0][1] = 0;
	a[1][1] = 1;
	a[2][1] = 2;
	for (int i = 3; i <= n; i++)
	{
		for (int j = 1; j < 1003; j++)
		{
			a[i][j] += a[i - 1][j] + a[i - 2][j];
			if (a[i][j] > 9)
			{
				a[i][j + 1]++;
				a[i][j] %= 10;

			}
		}
		
	}
	
		for (int j = 1003; j >= 1; j--)
		{
			if (a[n][j] == 0 && !m)
			{
				continue;
			}
			m = 1;
			printf("%d", a[n][j]);
		}
	
	return 0;
}