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)

#include <bits/stdc++.h>
using namespace std;

void ti(){
  #ifndef ONLINE_JUDGE
    freopen("in.txt", "r+", stdin);
    freopen("out.txt", "w", stdout);
  #endif
}

int main(){

  // ti();
  string s; cin>>s;
  string t; cin>>t;

  int diff = 0;
  for(int i = 0; i < s.length(); i++){
    if(s[i] != t[i]){
      diff++;
    }
  }

  cout<<diff<<endl;
  return 0;
}