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: Runtime Error)

#include <stdio.h>
#include <string.h>


//int count(char *x,char *y){
//
   //// size_t n=strlen(*x);

//}

int main(void){
    char *x,*y;
    char a,b;
    printf("x=");
    scanf("%s",&a);

    printf("y=");
    scanf("%s",&b);
    *x=a;
    *y=b;
    size_t n=strlen(x);
    int count;
    for (int i=0;i<=n;i++){
        if (x[i]!=y[i]){
            count+=1;
        }

    }
    printf("%d",count);

    return 0;
}