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 endl "\n"
#define F first
#define S second
#define pb push_back
#define mp make_pair

const int MOD = 1000000007;
const int N = 1e5 + 18;



int32_t main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
#endif
    int t = 1;
    //cin >> t;
    while (t--) {


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

}