#include <bits/stdc++.h> using namespace std; int main( ) { long n; cin>>n; long j1=1,j2=1,j3=0,i=1; if(n==1||n==2) { cout<<j1; } else if(n%3==0) { while(i<=(n/3)) { i+=1; j3=j1+j2; j1=j2+j3; j2=j3+j1; } cout<<j3; } else if(n%3==1) { while(i<=(n-1)/3) { i+=1; j3=j1+j2; j1=j2+j3; j2=j3+j1; } cout<<j1; } else { while(i<=(n-2)/3) { i+=1; j3=j1+j2; j1=j2+j3; j2=j3+j1; } cout<<j2; } return 0; }