import java.util.Scanner;
public class Zifuchuanduibi {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sc=new Scanner(System.in);
String a=sc.nextLine();
String a2=sc.nextLine();
int[] m=new int[10]; //通途存字符的acs码;
int[] m2=new int[10];
int b=0;
//判断字符串长度是否相等
if(a.length()!=a2.length()) {
System.out.println("1");
}else {
//对字符串进行切割
for(int i=0;i<a.length();i++) {
m[i]=a.charAt(i);
m2[i]=a2.charAt(i);
}
int[] k=new int[10];
//对比字符串
for(int i=0;i<a.length();i++) {
if(m[i]==m2[i]) {
k[i]=2;
}
if(m[i]+32==m2[i]||m[i]==m2[i]+32) {
k[i]=3;
}
if(m[i]!=m2[i]&&m[i]+32!=m2[i]&&m[i]!=m2[i]+32) {
b=4;
System.out.println("4");
break;
}
}
if(k.length!=a.length()&&b==0) {
int o=0;
for(int i=0;i<a.length();i++) {
if(k[i]==3) {
o=1;
}
}
if(o==1) {
System.out.println("3");
}else {
System.out.println("2");
}
}
}
}
}
public class Zifuchuanduibi {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sc=new Scanner(System.in);
String a=sc.nextLine();
String a2=sc.nextLine();
int[] m=new int[10]; //通途存字符的acs码;
int[] m2=new int[10];
int b=0;
//判断字符串长度是否相等
if(a.length()!=a2.length()) {
System.out.println("1");
}else {
//对字符串进行切割
for(int i=0;i<a.length();i++) {
m[i]=a.charAt(i);
m2[i]=a2.charAt(i);
}
int[] k=new int[10];
//对比字符串
for(int i=0;i<a.length();i++) {
if(m[i]==m2[i]) {
k[i]=2;
}
if(m[i]+32==m2[i]||m[i]==m2[i]+32) {
k[i]=3;
}
if(m[i]!=m2[i]&&m[i]+32!=m2[i]&&m[i]!=m2[i]+32) {
b=4;
System.out.println("4");
break;
}
}
if(k.length!=a.length()&&b==0) {
int o=0;
for(int i=0;i<a.length();i++) {
if(k[i]==3) {
o=1;
}
}
if(o==1) {
System.out.println("3");
}else {
System.out.println("2");
}
}
}
}
}