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 Ruby (2.7.1) (judge verdict: Accepted)

#n,k=gets.split(' ').map(&:to_i)
#h=gets.split(' ').map(&:to_i)
#tajigen = Array.new(4) { Array.new(2,0) }
#BC = gets.chomp.to_i.times.map { gets.split.map(&:to_i) }
#bc=q.times.map{gets.split.map(&:to_i)}
s=gets.chomp
t=gets.chomp
count=0
for i in 0..s.length
  if s[i]!=t[i]
    count+=1
  end
end
#puts s.length
puts count