#include<bits/stdc++.h>

using namespace std;

int main(){
	string s1,s2;
	int ans;
	cin>>s1>>s2;
	if(s1.length()!=s2.length()){
		ans=1;
	}
	else{
		ans=2;
		for(int i=0;i<s1.length();i++){
			if(abs(int(s1[i]-s2[i]))==('a'-'A')) ans=3;
			else if(abs(int(s1[i]-s2[i]))!=int('a'-'A') and int(s1[i]-s2[i])!=0){
				ans=4;
				break;
			}
		}
	}
	cout<<ans<<endl;
	return 0;
}