Wilbur the pig is tinkering with arrays again. He has the array a1, a2, ..., an initially consisting of n zeros. At one step, he can choose any index i and either add 1 to all elements ai, ai + 1, ... , an or subtract 1 from all elements ai, ai + 1, ..., an. His goal is to end up with the array b1, b2, ..., bn. 

Of course, Wilbur wants to achieve this goal in the minimum number of steps and asks you to compute this value.

Input

The first line of the input contains a single integer n (1 ≤ n ≤ 200 000) — the length of the array ai. Initially ai = 0 for every position i, so this array is not given in the input.

The second line of the input contains n integers b1, b2, ..., bn ( - 109 ≤ bi ≤ 109).

Output

Print the minimum number of steps that Wilbur needs to make in order to achieve ai = bi for all i.

Examples

Input

5
1 2 3 4 5


Output

5

Input

4
1 2 2 1


Output

3

Note

In the first sample, Wilbur may successively choose indices 1, 2, 3, 4, and 5, and add 1 to corresponding suffixes.

In the second sample, Wilbur first chooses indices 1 and 2 and adds 1 to corresponding suffixes, then he chooses index 4 and subtract 1.
from collections import *
from itertools import *
from random import *
from bisect import *
from string import *
from queue import *
from heapq import *
from math import *
from re import *
from sys import *
def fast(): return stdin.readline().strip()
def zzz(): return [int(i) for i in fast().split()]


z, zz = input, lambda: list(map(int, z().split()))
szz, graph, mod, szzz = lambda: sorted(
    zz()), {}, 10**9 + 7, lambda: sorted(zzz())


def lcd(xnum1, xnum2): return (xnum1 * xnum2 // gcd(xnum1, xnum2))
def output(answer): stdout.write(str(answer))


dx = [-1, 1, 0, 0, 1, -1, 1, -1]
dy = [0, 0, 1, -1, 1, -1, -1, 1]


###########################---Test-Case---#################################
"""

If you Know me , Then you probably don't know me !

"""
###########################---START-CODING---##############################


# n, m = zzz()


# for _ in range(m):
#     x, y, w = zzz()
#     try:
#         graph[x]
#     except:
#         graph[x] = []
#     try:
#         graph[y]
#     except:
#         graph[y] = []
#     graph[x].append((y, w))
#     graph[y].append((x, w))


# path = [0] * (n + 1)
# dis = [float('inf')] * (n + 1)

# hp = [(0, 1)]

# while hp:
#     try:
#         dcur, cur = heappop(hp)
#         print(hp)
#         for d, w in graph[cur]:
#             if dcur + w < dis[d]:
#                 dis[d] = dcur + w
#                 path[d] = cur
#                 heappush(hp, (dis[d], d))
#                 print(hp)
#     except:
#         exit(print(-1))


# l = [n]
# x = n
# print(path)
# print(dis)
# if path[n] > 0:
#     while x != 1:
#         x = path[x]
#         l.append(x)
#     print(*l[::-1])
# else:
#     print(-1)


# #
# root = {}


# def build(string, index):
#     node = root
#     for letter in string:
#         if letter not in node:
#             node[letter] = {}
#         node = node[letter]
#     node['index'] = index


# def contains(string):
#     node = root
#     for letter in string:
#         if letter not in node:
#             return False
#         node = node[letter]
#     return node['index']


# n, l = zzz()
# s = fast() * 2
# q = int(fast())
# for i in range(q):
#     build(input(), i + 1)
# pos = False
# ans = [0] * n
# for i in range(l):
#     pos = True
#     found = [False] * (q + 1)
#     for j in range(n):
#         loc = contains(s[i + j * l: i + (j + 1) * l])
#         if not loc or found[loc]:
#             pos = False
#             break
#         found[loc] = True
#         ans[j] = loc
#     if pos:
#         break
# if not pos:
#     print("NO")
# else:
#     print("YES")
#     # print(' '.join([str(x) for x in ans]))
#     for i in ans:
#         print(i)

# num = int(z())

# for _ in range(num):
#     a, b = zzz()
#     arr = zzz()
#     for i in arr:
#         while 0 < i < b * 10 and i % b:
#             i -= 10
#         if i < b:
#             print('NO')
#         else:
#             print('YES', i)
# num = int(z())


# def has(x, d):
#     return str(x).count((str(d))) > 0


# for _ in range(num):
#     arr = zzz()
#     dp = [0] * (1005)
#     dp[0] = 1
#     for i in range(1, 1002):
#         if has(i, d):
#             for j in range(0, 1003 - i):
#                 if dp[j] > 0:
#                     dp[i + j] = 1
#     for i in arr:
#         if i > 1000 or dp[x]:
#             print('YES')
#         else:
#             print('NO')

# n, m = zzz()
# arr = list(fast() + '***')

# k, res = 0, []

# for i in range(n):
#     if arr[i] == arr[i + 1] == '.':
#         k += 1
# for i in range(m):
#     x, y = fast().split(' ')
#     x = int(x) - 1
#     if arr[x] == '.':
#         if y != '.':
#             if x > 0 and arr[x - 1] == '.':
#                 k -= 1
#             if x < n - 1 and arr[x + 1] == '.':
#                 k -= 1
#     else:
#         if y == '.':
#             if x > 0 and arr[x - 1] == '.':
#                 k += 1
#             if x < n - 1 and arr[x + 1] == '.':
#                 k += 1
#     print(k)
#     arr[x] = y


n = int(z())

arr = zzz()

ans = abs(arr[0])

for i in range(1, n):
    ans += abs(arr[i] - arr[i - 1])
print(ans)
