#include <stdio.h>
#include <stdlib.h>
#define INF 1000000001
 
void merge(int, int, int);
void mergeSort(int, int);
 
int n;
int A[200000];
int L[100001], R[100001];
long cnt = 0;
     
int main()
{
    int i;
    int n;
     
    scanf("%d", &n);
    for(i = 0; i < n; i++)
    {
        scanf("%d", &A[i]);
    }
     
    mergeSort(0, n);
 
    printf("%ld\n", cnt);
     
    return 0;
}
 
void mergeSort(int left, int right)
{
    int mid;
 
    if(left + 1 < right)
    {
        mid = (left + right)/2;
        mergeSort(left, mid);
        mergeSort(mid, right);
        merge(left, mid, right);
    }
}
 
void merge(int left, int mid, int right)
{
    int i, j, k;
    int n1, n2;
  
    n1 = mid - left;
    for(i = 0; i < n1; i++)
    {
        L[i] = A[left + i];
    }
    L[n1] = INF;
   
    n2 = right - mid;
    for(j = 0; j < n2; j++)
    {
        R[j] = A[mid + j];
    }
    R[n2] = INF;
 
    i = 0;
    j = 0;
    for(k = left; k < right; k++)
    {
        if(L[i] <= R[j])
        {
            A[k] = L[i];
            i++;
        }
        else
        {
            A[k] = R[j];
            cnt += n1 - i;
            j++;
        }
    }
}

