input: Write a function to compute the edit distance between two strings in Python. The function should return the minimum number of operations (insertions, deletions, or substitutions) required to change one string into the other. Given strings `string1` and `string2`, the function should return an integer representing the edit distance.
  assert editDistance("kitten", "sitting", len("kitten"), len("sitting"))==3
  assert editDistance("intention", "execution", len("intention"), len("execution"))==5
  assert editDistance("horse", "ros", len("horse"), len("ros"))==3
  assert editDistance("cat", "cut", len("cat"), len("cut"))==1
  assert editDistance("", "a", len(""), len("a"))==1
output: def editDistance(string1, string2, m, n):
      dp = [[0 for _ in range(n + 1)] for _ in range(m + 1)]
      
      for i in range(m + 1):
          for j in range(n + 1):
              if i == 0:
                  dp[i][j] = j
              elif j == 0:
                  dp[i][j] = i
              elif string1[i - 1] == string2[j - 1]:
                  dp[i][j] = dp[i - 1][j - 1]
              else:
                  dp[i][j] = 1 + min(dp[i - 1][j], dp[i][j - 1], dp[i - 1][j - 1])
      
      return dp[m][n]