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 rep(i,n) for(int i=0;i<(n);++i)
#define FOR(i,n,j) for(int i=(j);i<(n);++i)
#define rrep(i,n) for(int i=(n);i>=0;--i)
#define ssort(n) sort((n).begin(),(n).end())
using ll=long long;
using ld=long double;
typedef pair<int,int> P;
#define Yes cout << "Yes" << endl
#define No cout << "No" << endl
#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
#define INF 10101010

int main()
{
    string S,T;
    cin >> S;
    cin >> T;
    int count=0;
    rep(i,S.length()){
        if(S[i]!=T[i])count++;
    }  
    cout << count << endl;
}