https://www.luogu.com.cn/problem/P1068

#include<bits/stdc++.h>
using namespace std;
int a[1000001];
int main(){
	int n;
	cin>>n;
	for(int i=1;i<=n;i++){
		if(i%2==0) a[i]=a[i-1]+a[i/2];
		else  a[i]=a[i-1];
	}
	cout<<a[n];
}