import sys
from itertools import combinations, permutations, product, accumulate, groupby
from collections import defaultdict, deque, Counter
from functools import reduce
import heapq
import bisect
import math
import copy

sys.setrecursionlimit(10 ** 9)
input = lambda: sys.stdin.readline().rstrip()
INF = float("inf")
MOD = 10 ** 9 + 7
# DFS
# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')

#https://tjkendev.github.io/procon-library/python/sequence/number_of_inversions.html
N = int(input())
A = []
for i in range(N):
    A.append(int(input()))
# BIT
data = [0]*(N+1)
def add(k, x):
    while k <= N:
      data[k] += x
      k += k & -k
def get(k):
    s = 0
    while k:
        s += data[k]
        k -= k & -k
    return s

ans = 0
for i, a in enumerate(A):
    ans += (N - 1 - i) - get(a)
    add(a, 1)
print(ans)