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: Time Limit Exceeded)

 #include <stdio.h>
 #include <string.h>
 #define mxz 2e5+10
 char a[(int)mxz], b[(int)mxz];
  
 int main(void) {
 	int d = 0;
  
 	scanf("%s", a);
 	scanf("%s", b);
  	

 	if(strcmp(a, b) != 0){
 		for(int c = 0; c < strlen(a); c++){
 			if(a[c] != b[c]){
 				a[c] = b[c];
 				d++;
 			}
 		}
 		printf("%d", d);
 	}else{
 		printf("0");
 	}
  
 	return 0;
 }