造福人类

#include<bits/stdc++.h>
#pragma GCC optimize(3)
using namespace std;
const int N=1e7+10;
const int INF=0x3f3f3f3f;
int st,en,ans;
int Build(int x)
{
	int y=x;
	while(x)
	{
		y*=10;
		y+=x%10;
		x/=10;
	}
	return y;
}
bool Check(int x)
{
	int year=x/10000,month=x/100%100,date=x%100;
	if(date>=32 || date<=0)return 0;
	if(month==1||month==3||month==5||month==7||month==8||month==10||month==12)
	{
		if(date>31)return 0;
	}
	else if(month==4||month==6||month==9||month==11)
	{
		if(date>30)return 0;
	}
	else if(month==2)
	{
		if(year%400==0 || (year%100!=0 && year%4==0))
	    {
		    if(date>=30)
			{
				return 0;
			}
		}
		else
		{
			if(date>=29)
			{
					return 0;
			}
		}
	}
	else
	{
		return 0;
	}
	return 1;
}
int main()
{
	cin>>st>>en;
	for(int i=1000;i<=9999;++i)
	{
		int k=Build(i);
		if(Check(k) && k>=st && k<=en)
		{
			//cout<<k<<endl;
			ans++;
		}
	}
	cout<<ans;
    return 0;
}