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;

#define int long long 
#define dou  double 
#define endl "\n"

const int MOD=1e9+7;

void solve()
{
	string str1,str2;
	int cnt=0,i;
	cin >> str1 >> str2;
	for(i=0;i<str1.size();i++)
	{
		if(str1[i]!=str2[i])
			cnt++;
	}
	cout << cnt << endl;
}

main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	
	solve();
}