input: Write a python function to calculate the edit distance between two strings.
  assert editDistance("kitten", "sitting", 6, 7) == 3
  assert editDistance("flaw", "lawn", 4, 4) == 2
  assert editDistance("intention", "execution", 9, 9) == 5
output: def editDistance(str1, str2, m, n):
      dp = [[0 for x in range(n + 1)] for x 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 str1[i - 1] == str2[j - 1]:
                  dp[i][j] = dp[i - 1][j - 1]
              else:
                  dp[i][j] = 1 + min(dp[i][j - 1],    # Insert
                                     dp[i - 1][j],    # Remove
                                     dp[i - 1][j - 1]) # Replace
  
      return dp[m][n]