diff --git a/field.py b/field.py
index 93dbeed..138cc4b 100644
--- a/field.py
+++ b/field.py
@@ -2,6 +2,7 @@ import random
 import time
 from heapq import *
 from enum import Enum, IntEnum
+from queue import PriorityQueue
 from collections import deque
 
 import pygame
@@ -12,12 +13,12 @@ WHITE = (200, 200, 200)
 BLUE = (46, 34, 240)
 WINDOW_DIMENSIONS = 900
 BLOCK_SIZE = 60
-ROCKS_NUMBER = 15
+ROCKS_NUMBER = 20
 VEGETABLES_NUMBER = 20
 VEGETABLES = ('Potato', 'Broccoli', 'Carrot', 'Onion')
 BOARD_SIZE = int(WINDOW_DIMENSIONS / BLOCK_SIZE)
 WATER_TANK_CAPACITY = 10
-GAS_TANK_CAPACITY = 100
+GAS_TANK_CAPACITY = 250
 SPAWN_POINT = (0, 0)
 
 tractor_image = pygame.transform.scale(pygame.image.load("images/tractor_image.png"), (BLOCK_SIZE, BLOCK_SIZE))
@@ -92,7 +93,7 @@ def draw_interface():
             elif event.type == pygame.MOUSEBUTTONDOWN:
                 startpoint = (tractor.x, tractor.y, tractor.direction)
                 endpoint = get_click_mouse_pos()
-                a, c = graph1.dijkstra(startpoint, endpoint)
+                a, c = graph1.a_star(startpoint, endpoint)
                 b = getRoad(startpoint, c, a)
                 movement(tractor, grid, b)
         updateDisplay(tractor, grid)
@@ -169,32 +170,31 @@ class Graph:
                 for direction in Direction:
                     self.graph[(x, y, direction)] = get_next_nodes(x, y, direction, grid)
 
-    def dijkstra(self, start, goal):
+    def a_star(self, start, goal):
         # not finished yet https://www.youtube.com/watch?v=abHftC1GU6w
-        queue = []
-        heappush(queue, (0, start))
+        queue = PriorityQueue()
+        queue.put((0, start))
         cost_visited = {start: 0}
         visited = {start: None}
 
         returnGoal = goal
+        h = lambda start, goal: abs(start[0] - goal[0]) + abs(start[1] - goal[1]) #heuristic function (manhattan distance)
 
-        while queue:
-            cur_cost, cur_node = heappop(queue)
+        while not queue.empty():
+            cur_cost, cur_node = queue.get()
             if cur_node[0] == goal[0] and cur_node[1] == goal[1]:
-                queue = []
                 returnGoal=cur_node
                 break
 
             next_nodes = self.graph[cur_node]
-            # print()
             for next_node in next_nodes:
                 neigh_cost, neigh_node = next_node
-                # print(neigh_node)
-                new_cost = cost_visited[cur_node] + neigh_cost
+
+                new_cost = cost_visited[cur_node] + neigh_cost + h(neigh_node, goal)
 
                 if neigh_node not in cost_visited or new_cost < cost_visited[neigh_node]:
-                    heappush(queue, (new_cost, neigh_node))
-                    cost_visited[neigh_node] = new_cost
+                    queue.put((new_cost, neigh_node))
+                    cost_visited[neigh_node] = new_cost - h(neigh_node, goal)
                     visited[neigh_node] = cur_node
         # print(visited, returnGoal)
         return visited, returnGoal
@@ -233,9 +233,9 @@ class Tractor:
                 self.x -= 1
 
         if grid.grid[self.x][self.y] == types.ROCK:
-            self.gas -= 5
+            self.gas -= 12
         else:
-            self.gas -= 1
+            self.gas -= 2
         return
 
 
@@ -253,9 +253,9 @@ def get_next_nodes(x, y, direction: Direction, grid: Grid):
             if check_next_node(x + way[0], y + way[1]):
                 if grid.grid[x + way[0]][y + way[1]] == types.ROCK:
                     # print(x, y, "to", x + way[0], y + way[1], 'costs 5')
-                    next_nodes.append((5, (x + way[0], y + way[1], new_direction)))
+                    next_nodes.append((12, (x + way[0], y + way[1], new_direction)))
                 else:
-                    next_nodes.append((1, (x + way[0], y + way[1], new_direction)))
+                    next_nodes.append((2, (x + way[0], y + way[1], new_direction)))
 
     # print(x,y, direction, next_nodes, '\n')
     return next_nodes