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 <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#define findmax(a,b) (a)>(b)?(a):(b)
#define findmin(a,b) (a)<(b)?(a):(b)
#define inout freopen("in.txt","r",stdin);freopen("out.txt","w",stdout)
#define swap(a,b) (a)+=(b);(b)=(a)-(b);(a)-=(b)
#define quicksort(a,n) qsort(a,n,sizeof(a[0]),cmp)
#define inputarr(a,n) for(int i=0;i<n;i++){scanf("%d",&a[i]);}
#define printarr(a,n) for(int i=0;i<n;i++){printf("%d ",a[i]);}puts("");
int cmp(const void *a,const void *b){return *(int *)a - *(int *)b;}

int main() {
    //inout;

  
    char s[200005];

    char t[200005];

    int cnt = 0;
    
    scanf("%s%s", s, t);

    for(int i = 0; s[i]; i++){
    	if(s[i] != t[i]){
    		cnt++;
    	}
    }

    printf("%d", cnt);

}