10223.cpp

#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
int main(){
    int catalan[]={0,1,2,5,14,42,132,429,1430,4862,16796,58786,208012,742900,2674440,9694845,35357670,129644790,477638700,1767263190};
    int max=20;
    int n;
    while(scanf("%d",&n)!=EOF){
                                for(int i=1;i<=20;i++){
                                        if(n==catalan[i]){
                                                         printf("%d\n",i);
                                                         break;
                                        }
                                }
    }
    return 0;
}