#include <iostream>
#include <fstream>

void Merge(long* arr, int begin, int end, long long* p_a) {

    int i = begin;
    int mid = begin + (end - begin) / 2;
    int j = mid + 1;
    int k = 0;

    long d[end - begin];


    while (i <= mid && j <= end) {
        if (arr[i] <= arr[j]) {
            d[k] = arr[i];
            i++;
        }
        else {
            d[k] = arr[j];
            j++; *p_a += mid + 1 - i;
        }
        k++;
    }

    while (i <= mid) {
        d[k] = arr[i];
        i++; k++;
    }

    while (j <= end) {
        d[k] = arr[j];
        j++; k++;
    }

    for (i = 0; i < k; ++i) {
        arr[begin + i] = d[i];
    }

}

void Merge_Sort(long* arr, int left, int right, long long* p_a) {

    if (left < right) {
        if (right - left == 1) {
            if (arr[left] > arr[right]) {
                std::swap(arr[left], arr[right]);
                *p_a += 1;
            }
        }
        else {
            Merge_Sort(arr, left, left + (right - left) / 2, p_a);
            Merge_Sort(arr, left + (right - left) / 2 + 1, right, p_a);
            Merge(arr, left, right, p_a);
        }
    }
}

int main() {
    int n;
    long long a;
    long long* p_a = &a;

    std::ifstream in("inversions.in");
    in >> n;

    long arr[n];

    for (int i = 0; i < n; ++i) {
        in >> arr[i];
    }

    Merge_Sort(arr, 0, n - 1, p_a);

    std::ofstream out("inversions.out");
    out << *p_a;

    return 0;
}