package main

import "fmt"

func merge(a, b []int, cnt *int) []int {
    res := make([]int, len(a)+len(b))
    var i, j int

    for i < len(a) && j < len(b) {
        if a[i] <= b[j] {
            res[i+j] = a[i]
            i++
        } else {
            res[i+j] = b[j]
            *cnt += len(a) - i
            j++
        }
    }

    for ; i < len(a); i++ {
        res[i+j] = a[i]
    }
    for ; j < len(b); j++ {
        res[i+j] = b[j]
    }

    return res
}

func MergeSort(a []int, cnt *int) []int {
    if len(a) < 2 {
        return a
    }

    mid := len(a)/2
    left := MergeSort(a[:mid], cnt)
    right := MergeSort(a[mid:], cnt)

    return merge(left, right, cnt)
}

func main() {
    var n int
    fmt.Scanf("%d", &n)

    nums := make([]int, n)
    for i := 0; i < n; i++ {
        fmt.Scanf("%d", &nums[i])
    }

    cnt := 0
    MergeSort(nums, &cnt)
    fmt.Println(cnt)
}