n = int(input())
arr = []
for i in range(n):
    x, y = input().split()
    x = int(x)
    y = int(y)
    arr.append((x, y))
arr.sort()
st = True
x1 = 0
y1 = 0
res = 0
i = 0
dp = []
while i < n:
    j = i
    x1, y1 = arr[i]
    x, y = x1, y1
    b = []
    while j < len(arr) and x == x1:
        b.append(y)
        j += 1
        if j < len(arr):
            x, y = arr[j]
    if j != len(arr):
        res += x - x1
    maxy = max(b)
    miny = min(b)
    if len(dp) > 0:
        dp.append([0, 0])
        if prev_max > maxy:
            dp[-1][0] = dp[-2][1] + (prev_max - miny)
        else:
            dp[-1][0] = dp[-2][1] + (maxy - prev_max) + (maxy - miny)
        if prev_min < miny:
            dp[-1][1] = dp[-2][0] + (maxy - prev_min)
        else:
            dp[-1][1] = dp[-2][0] + (prev_min - miny) + (maxy - miny)
        if len(dp) > 1:
            dp[-1][1] = min(dp[-1][1], dp[-2][1] + abs(prev_max - miny) + (maxy - miny))
            dp[-1][0] = min(dp[-1][0], dp[-2][0] + abs(maxy - prev_min) + (maxy - miny))
    else:
        dp.append([0, 0])
        dp[-1][0] = maxy - miny
        dp[-1][1] = maxy - miny
    prev_max = maxy
    prev_min = miny
    i = j
print(min(dp[-1]) + res)
"""for i in arr:
    x, y = i
    if st:
        x1, y1 = x, y
        st = False
    else:
        res += abs(x - x1) + abs(y - y1)
        x1, y1 = x, y
print(res)"""