n1 = input()
n2 = input()
c4 = 0
c7 = 0
for i in range(len(n1)):
if n1[i] != n2[i]:
if n1[i] < n2[i]:
c4 += 1
elif n1[i] > n2[i]:
c7 += 1
print(max(c4,c7))
275. H-Index II | 274. H-Index |
260. Single Number III | 240. Search a 2D Matrix II |
238. Product of Array Except Self | 229. Majority Element II |
222. Count Complete Tree Nodes | 215. Kth Largest Element in an Array |
198. House Robber | 153. Find Minimum in Rotated Sorted Array |
150. Evaluate Reverse Polish Notation | 144. Binary Tree Preorder Traversal |
137. Single Number II | 130. Surrounded Regions |
129. Sum Root to Leaf Numbers | 120. Triangle |
102. Binary Tree Level Order Traversal | 96. Unique Binary Search Trees |
75. Sort Colors | 74. Search a 2D Matrix |
71. Simplify Path | 62. Unique Paths |
50. Pow(x, n) | 43. Multiply Strings |
34. Find First and Last Position of Element in Sorted Array | 33. Search in Rotated Sorted Array |
17. Letter Combinations of a Phone Number | 5. Longest Palindromic Substring |
3. Longest Substring Without Repeating Characters | 1312. Minimum Insertion Steps to Make a String Palindrome |