diff --git a/Sudoku.py b/Sudoku.py
index 6afd584..4f8165c 100644
--- a/Sudoku.py
+++ b/Sudoku.py
@@ -1,14 +1,17 @@
 from random import randint
 
 class Sudoku:
+    LENGTH = 9
+    EMPTY = 0
+
     def __init__(self):
         self.generateBoard()
     
     def emptyArray(self):
-        return [0 for i in range(9)]
+        return [self.EMPTY for i in range(self.LENGTH)]
 
     def emptyMatrix(self):
-        return [self.emptyArray() for i in range(9)]
+        return [self.emptyArray() for i in range(self.LENGTH)]
     
     def generateBoard(self):
         self.rows = self.emptyMatrix()
@@ -18,18 +21,25 @@ class Sudoku:
     
     def getColumns(self):
         columns = self.emptyMatrix()
-        for i in range(9):
-            for j in range(9):
-                columns[i][j] = self.rows[j][i]
+        for i in range(self.LENGTH):
+            for j in range(self.LENGTH):
+                columns[i][j] = self.getRows()[j][i]
         return columns
     
     def getBlocks(self):
         blocks = self.emptyMatrix()
-        for i in range(9):
-            for j in range(9):
-                blocks[i][j] = self.rows[i // 3 * 3 + j // 3][i % 3 * 3 + j % 3]
+        for i in range(self.LENGTH):
+            for j in range(self.LENGTH):
+                blocks[i][j] = self.getRows()[i // 3 * 3 + j // 3][i % 3 * 3 + j % 3]
         return blocks
     
+    def getEmptyCells(self):
+        arr = []
+        for i in range(self.LENGTH):
+            for j in range(self.LENGTH):
+                arr.append([i, j]) if self.getRows()[i][j] == self.EMPTY else ''
+        return arr
+    
     def isInRow(self, num, row):
         return num in self.getRows()[row]
 
@@ -42,33 +52,42 @@ class Sudoku:
     def isPlaceble(self, num, row, col):
         return not (self.isInRow(num,row) or self.isInColumn(num,col) or self.isInBlock(num,row // 3 * 3 + col // 3))
 
+    def setNumber(self, num, row, col):
+        self.getRows()[row][col] = num if self.isPlaceble(num, row, col) else self.EMPTY
+
     def placeRandomNumber(self, row, col):
         nums = [num for num in range(1, 10)]
         num = nums.pop(randint(0, len(nums) - 1))
         while not self.isPlaceble(num, row, col) and len(nums) > 0:
             num = nums.pop(randint(0, len(nums) - 1))
-        self.rows[row][col] = num if self.isPlaceble(num, row, col) else ' '
+        self.setNumber(num, row, col)
     
     def randomize(self):
-        for i in range(9):
-            for j in range(9):
-                self.placeRandomNumber(i, j)
+        while len(self.getEmptyCells()) > 2:
+            self.generateBoard()
+            self.randomizeEmptyCells()
+    
+    def randomizeEmptyCells(self):
+        emptyCells = self.getEmptyCells()
+        while len(emptyCells) > 0:
+            self.placeRandomNumber(*emptyCells.pop())
 
     def printHDivider(self):
         print('+ - - - + - - - + - - - +')
     
     def printRow(self, numRow):
         row = '| '
-        for i in range(len(self.rows[numRow])):
-            row += f'{self.rows[numRow][i]} ' + ('| ' if (i % 3 == 2) else '')
+        for i in range(self.LENGTH):
+            row += f'{self.getRows()[numRow][i]} ' + ('| ' if (i % 3 == 2) else '')
         print(row)
     
     def printBoard(self):
         self.printHDivider()
-        for i in range(len(self.rows)):
+        for i in range(self.LENGTH):
             self.printRow(i)
             self.printHDivider() if i % 3 == 2 else ''
 
 sudoku = Sudoku()
 sudoku.randomize()
+print(sudoku.getEmptyCells())
 sudoku.printBoard()
\ No newline at end of file