uva 10223

#include<stdio.h>
int main()
{
    long int s[19]={1,2,5,14,42,132,429,1430,4862,16796,58786,208012,742900,2674440,9694845,35357670,129644790,477638700,1767263190};
    int  n,i;
    while(scanf("%d",&n)==1)
    {
        for(i=0;i<19;i++)
        {
            if(n==s[i])
            {
                printf("%d\n",i+1);
                break;

            }
        }
    }
    return 0;
}