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)

#pragma region Header
#define _CRT_SECURE_NO_WARNINGS
#define FOR(i,s, e) for(int i = s; i<e; ++i)
#define rFOR(i,s, e) for(int i=s-1; i>=e; --i)
#define loop(len) for(int i=0; i<len; ++i)
#define rloop(len) for(int i=len-1; i>=0; --i)
#define iPair pair<int,int>
#define LPair pair<ll,ll>
#define vecP(t,t2) vector<pair<t,t2>>
#define uoMP(t, t2) unordered_map<t, t2>
#define pb push_back
#define pp pop_back
#define beg_end(v) v.begin(), v.end()
#define Sort(v) sort(v.begin(), v.end())
#define rSort(v) sort(v.rbegin(), v.rend())
#define rev(v) reverse(v.begin(), v.end())
#define MrN ios::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
typedef long long  ll;
typedef long double  ld;
#include<bits/stdc++.h>
using namespace std;
#pragma endregion

string s, t;
int ans;

int main() {
	MrN;
	// freopen("input.txt", "r", stdin);
	cin >> s >> t;
	loop(s.size()){
		if(s[i] != t[i])
			ans++;
	}

	cout << ans << '\n';
	return 0;
}