import java.util.*;
import java.io.*;

public class Main{
    public static int N = 100010;
    public static int n;
    public static int a[] = new int[N];

    public static long mergeSort(int[] arr,int left,int right){
        if(left >= right) return 0;

        int mid = (left + right) / 2 ;
        long result = mergeSort(arr,left,mid) + mergeSort(arr,mid + 1,right);

        int[] temp = new int[right - left + 1];
        int k = 0,i = left,j = mid + 1;
        while(i <= mid && j <= right){
            if(arr[i] <= arr[j]) temp[k ++ ] = arr[i ++ ];
            else{
                temp[k ++ ] = arr[j ++ ];
                result += mid - i + 1;
            }
        }
        while(i <= mid) temp[k ++ ] = arr[i ++ ];
        while(j <= right) temp[k ++ ] = arr[j ++ ];

        for(i = left,j = 0;i <= right;i++,j++){
            arr[i] = temp[j];
        }
        return result;
    }


    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        String str = br.readLine();
        n = Integer.parseInt(str);
        String[] s = br.readLine().split(" ");
        for(int i = 0;i < n;i ++) a[i] = Integer.parseInt(s[i]);
        long resault = mergeSort(a,0,n-1);
        bw.write(String.valueOf(resault));
        bw.close();
    }
}