http://oj.ecustacm.cn/problem.php?id=1420

#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
int main(void)
{
	string a,b; cin>>a>>b;
	if(a.size()!=b.size()) 
	{
		cout<<1<<endl;
		return 0;
	}
	if(a==b)
	{
		cout<<2<<endl;
		return 0;
	}
	int i;
	for(i=0;i<a.size();i++)
	{
		char temp1=a[i]+32;
		char temp2=a[i]-32;
		if(temp1!=b[i] && temp2!=b[i] && a[i]!=b[i])
				break;
	}
	if(i==a.size())
	{
		cout<<3<<endl;
		return 0;
	}
	if(a!=b)
	{
		cout<<4<<endl;
		return 0;
	}
	return 0;
}