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>
#define fasterthanlight ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define test int T; cin>>T; while(T--)
#define endl "\n"
#define int long long
#define vi vector<int>
#define pb push_back
#define mod 1000000007
#define MAX 1e9
#define MIN -1e9
#define hi "visited\n" //sasta debugging
using namespace std;

//author::@whohet-->Het Patel
//anscii A-65 Z-90   a-97 z-112
//vector<int>v;
//vector<char>v;
//char arr[100005];
//int a[26];
//a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,t,
signed main()
{
    fasterthanlight;
    string s;
    string t;
    cin >> s >> t;
    int sum = 0;
    for (int i = 0; i < s.length(); i++)
    {
        if (s[i] != t[i])
            sum++;
    }
    cout << sum;

    //cout << "\n\n"<<"Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " seconds.\n";
    return 0;
}