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++ (Clang 10.0.0) (judge verdict: Accepted)

#include <algorithm>
#include <iostream>
#include <math.h>
#include <stdio.h>
#include <string>
#include <stack>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)

using namespace std;
typedef long long int ll;
const ll modP = 1000000007;


int main()
{
	string s,t;
	cin>>s>>t;
	ll ans = 0;
	for(int i = 0; i < s.size(); i++){
		if(s[i] != t[i]) ans++;
	}
	cout<<ans<<endl;
	return 0;
}