#include<iostream>
using namespace std;
int main(){
	int n,len=1;
	int fib[5010][100];
	cin>>n;
	fib[1][0]=1;fib[2][0]=2;
	if(n<=3){
		cout<<n;
		return 0;
	}
	for(int i=3;i<=n;i++){
		for(int j=0;j<len;j++){
			fib[i][j]=fib[i-1][j]+fib[i-2][j];
			fib[i][j+1]+=fib[i][j]/1000;
			fib[i][j]%1000;
			if(fib[i][len+1]) len++;
		}
	}
	for(int i=len-1;i>=0;i--) cout<<fib[n][i];
	return 0;
}