Problem:
Score : 200 points

Problem Statement

Given are strings S and T. Consider changing S to T by repeating the operation below. Find the minimum number of operations required to do so.

Operation: Choose one character of S and replace it with a different character.

Constraints

S and T have lengths between 1 and 2\times 10^5 (inclusive).

S and T consists of lowercase English letters.

S and T have equal lengths.

Input

Input is given from Standard Input in the following format:

S
T

Output

Print the answer.

Sample Input 1

cupofcoffee
cupofhottea

Sample Output 1

4

We can achieve the objective in four operations, such as the following:

First, replace the sixth character c with h.

Second, replace the eighth character f with t.

Third, replace the ninth character f with t.

Fourth, replace the eleventh character e with a.

Sample Input 2

abcde
bcdea

Sample Output 2

5

Sample Input 3

apple
apple

Sample Output 3

0

No operations may be needed to achieve the objective.

Solution in C++ (GCC 9.2.1) (judge verdict: Accepted)

  //shan61916
#include <bits/stdc++.h>
  using namespace std;
typedef   long long ll;
typedef   unsigned long long ull ;
typedef   double dll ;

#define   mp make_pair
#define   pb push_back
#define   ff first 
#define   ss second
#define   IOS ios::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define   endl "\n" 
#define   pll pair<ll, ll>
#define   all(x) x.begin(), x.end()
#define   vll vector<ll> 

const ll inf = (ll)(1e17 + 17);
const ll mod = (ll)(1e9 + 7);


int main(){
 IOS
#ifdef SHAN
    freopen("input.txt" , "r" , stdin);  
#endif
  string s, t;
  cin >> s >> t;
  ll ct = 0;
  for(ll i = 0; i < s.length(); i++) {
  	if(s[i] != t[i]) ct++;
  }
  cout << ct;
  return 0;
} //good night.