#include <iostream>
#include <fstream>
#include <functional>
using namespace std;

int count=0;

void merge(int mas[], int left, int mid, int right) {
    int i, j, k;
    int n1 = mid - left + 1;
    int n2 =  right - mid;


    int L[n1], R[n2];

    for (int i = 0; i < n1; i++)
        L[i] = mas[left + i];
    for (int j = 0; j < n2; j++)
        R[j] = mas[mid + 1+ j];

    i = j = 0;
    k = left;
    while (i < n1 && j < n2)
    {
        if (L[i] <= R[j])
        {
            mas[k] = L[i];
            i++;
        }
        else
        {
            mas[k] = R[j];
            j++;
            count=count+(n1-i);
        }

        k++;
    }
    while (i < n1)
    {
        mas[k] = L[i];
        i++;
        k++;
    }

    while (j < n2)
    {
        mas[k] = R[j];
        j++;
        k++;
    }

}

void merge_sort(int *mas,int left, int right) {
    int n=0;
    int mid;
    if (right<=left)
    {
        exit;
    }
    else
    {
        mid = (left+right)/2;
        merge_sort(mas,left,mid);
        merge_sort(mas,mid+1,right);
        merge(mas,left,mid,right);
    }

}

int main() {
    ifstream input("D:\\pascal\\input.txt");
    ofstream output("output.txt");

    int n=0;
    input >> n;
    int a[n-1];
    for (int i=0; i<n; i++)
    {
        input>>a[i];
    }

    merge_sort(a,0,n-1);
    cout<< count<< endl;
    output << count;
    return 0;
}