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 oo (long long)1e18
#define ll long long
#define setdp memset(dp,-1,sizeof(dp))
const ll mod = 1e9+7;
void _IOS(){ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);cin.sync_with_stdio(0);}
#define PI 3.14159265359
ll n,l,r,x;
    int b[200009],a[200009];
int main()
{
    string s,t;
    cin>>s>>t;
    n=s.length();
    int ans=0;
    for(int i=0;i<n;i++)
        if(s[i]!=t[i])
            ans++;
        cout<<ans;
}