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 main()
{
    int i,j=0,count=0,flag=0;
    char str[30];
    char str1[30];
    scanf("%s",str);
    scanf("%s",str1);
    printf("%s\n",str);
    printf("%s",str1);
    int m=strlen(str);
    int n=strlen(str1);
    for(i=0;i<m;i++)
    {
        
            if(str[i]==str1[j])
            {
                count++;
                j++;
            }
    }
    printf("%d",count);
    return 0;
}