from collections import deque
def bfs(start, target):
queue = deque([(start[0], start[1], 0)]) # (x, y, distancia)
visited = set()
visited.add((start[0], start[1]))
while queue:
x, y, dist = queue.popleft()
if (x, y) == target:
return dist
for dx, dy in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
nx, ny = x + dx, y + dy
if (nx, ny) not in visited:
visited.add((nx, ny))
queue.append((nx, ny, dist + 1))
return float('inf')
def solve_coin_collecting(N, coin_positions):
targets = [(x, y) for x in range(1, N + 1) for y in range(1, 3)]
total_moves = 0
used_targets = set()
for coin in coin_positions:
min_moves = float('inf')
best_target = None
for target in targets:
if target not in used_targets:
moves = bfs(coin, target)
if moves < min_moves:
min_moves = moves
best_target = target
total_moves += min_moves
used_targets.add(best_target)
return total_moves
import sys
input = sys.stdin.read
data = input().split()
N = int(data[0])
coin_positions = [(int(data[i * 2 + 1]), int(data[i * 2 + 2])) for i in range(2 * N)]
result = solve_coin_collecting(N, coin_positions)
print(result)
