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 watch(x) cerr <<"\e[91m"<<__func__<<": "<< #x << " = " << x <<"\e[39m"<< "\n"
typedef pair<int, int> pii;
typedef long long ll;
const double eps = 1e-9;
const int inf = 0x3f3f3f3f;


int main()
{
#ifndef ONLINE_JUDGE
    freopen("../io/in.txt", "r", stdin);
    //freopen("../io/out.txt", "w", stdout);
#endif // ONLINE_JUDGE
    string a, b;
    cin >> a >> b;
    int dif = 0;
    for(int i=0; i<a.size(); i++) if(a[i] != b[i]) dif++;
    cout << dif << endl;
    return 0;
}