#include <stdio.h>
#include <string.h>
#include <math.h>
#define max 1000

int sodep(int a)
{
    int i,b[max],c[max],len=0,count1=0,count2=0;
    while (a!=0)//cho cac chu so vao mang b
    {
        b[len]=a%10;
        a/=10;
        len++;
    }
    for (i=0;i<len;i++)
        c[i]=b[i];
    for (i=0;i<len;i++)//dao nguoc lai mang b de so sanh
        b[i]=c[len-i-1];
    for (i=0;i<len-1;i++)//123 thi so sanh tu 1 voi 2, 2 voi 3
    {
        if (b[i+1]==b[i]+1)
            count1++;
        else if (b[i+1]==b[i]-1)
            count1++;
        else //neu ko giam hoac tang dan thi break, return 0
        {
            count2++;
            break;
        }
    }
    if (count2!=0)
        return 0;
    else return 1;
}
int main()
{
    int n,j,dem=0;
    scanf("%d",&n);
    for (j=pow(10,n-1);j<=pow(10,n);j++)
        if(sodep(j)==1)
            dem++;
    printf("%d",dem);
    return 0;
}