package com.company;

import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.Scanner;

public class Main {
public static void main(String[] args) throws FileNotFoundException {
Scanner in = new Scanner(new FileReader("input.txt"));

String str1 = in.next();
String str2 = in.next();

in.close();

int n = 0;
n = str1.length();

int res = 4;

boolean all = true;
for(int i = 0; i < n; i++){
if(str1.charAt(i) != '?'){
all = false;
}
if(str2.charAt(i) != '?'){
all = false;
}
}

int k1=0, k2=0;
for(int i = 0; i < n; i++){
char cur1 = str1.charAt(i);
char cur2 = str2.charAt(i);
char a[] = new char[4];
char b[] = new char[4];

if(cur1 == '?' || cur2 == '?')
res = res;
else {
if((cur1 >= 'a' && cur1 <= 'g')
|| (cur2 >= 'a' && cur2 <= 'g')){
if(cur1 >= 'a' && cur1 <= 'g'){
k1 = 4;
}
if(cur2 >= 'a' && cur2 <= 'g'){
k2 = 4;
}
}
if((cur1 >= '0' && cur1 <= '9')
|| (cur2 >= '0' && cur2 <= '9')){
if(cur1 >= '0' && cur1 <= '9') {
k1 = 1;
}
if(cur2 >= '0' && cur2 <= '9'){
k2 = 1;
}
}

if(k1 == k2){
if(k1 == 1) {
if (cur1 != cur2)
res = 0;
else
res = 1;
}
} else {
if(k1 == 1){
if(!(cur1 > (char)(cur2-49) && cur1 < (char)(cur2-46))){
res = 0;
return;
}
} else {
if(!(cur2 > (char)(cur1-49) && cur2 < (char)(cur1-46))){
res = 0;
return;
}
else
res = 1;
}
}
}
}
if(all) System.out.println(9);
else System.out.println(res);
}

private static int min(int a, int b) {
if(b == 0)
return 0;
else
if(b > a)
return b;
else
return a;
}

private static int is(int a, int b, int last) {
if(Math.abs(a-b)>3)
return 0;
else
if(last > 4-Math.abs(a-b))
return 4-Math.abs(a-b);
else
return last;
}
}