C++ :

#include<bits/stdc++.h>
using namespace std;
char dx(char c){
   if(c >= 'a' && c <= 'z'){
   	  return c - 32;
   }else{
   	  return c;
   }	
}
int main(){
   string s1,s2;
   cin>>s1>>s2;
   if(s1.size() != s2.size()){
   	  cout<<1<<endl;
   }else{
   	  if(s1 == s2){
   	     cout<<2<<endl; 	
	  }else{
	  	 int t = 3;
	  	 for(int i = 0;i < s1.size();i++){
	  	   if(s1[i] != s2[i] && dx(s1[i]) != dx(s2[i])){
	  	     t = 4;
			 break; 	
		   } 	
	     }  
	     cout<<t<<endl;
	  }
   }  
   return 0;
}

Python :

n=input().strip()
m=input().strip()
if len(n)==len(m):
    if n==m:
        print(2)
    elif n.upper()==m.upper():
        print(3)
    else:
        print(4)
else:
    print(1)