【算法：3】数的计数

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cmath>

using namespace std;

inline int read()
{
    int x=0,f=1;char ch=getchar();
    for(;!isdigit(ch);ch=getchar()) if(ch==‘-‘) f=-1;
    for(;isdigit(ch);ch=getchar()) x=x*10+ch-‘0‘;
    return x*f;
}

int n,ans;

void dfs(int m)
{
    ans++;
    for(int i=1;i<=m/2;i++) dfs(i);
    return ;
}

int main()
{
    n=read();
    dfs(n);
    printf("%d\n",ans);
}