public static void main(String[] args)throws Exception {

int answer;

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

int N = Integer.parseInt(br.readLine());

int[] a = new int[N];

StringTokenizer st = new StringTokenizer(br.readLine());

for(int i=0;st.hasMoreTokens();i++){

a[i] = Integer.parseInt(st.nextToken());

}

long t1 = System.currentTimeMillis();

answer = countingInversions(a);

long t2 = System.currentTimeMillis();

BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

bw.write(answer+"");

bw.newLine();

bw.flush();

bw.close();

System.out.println("duration="+(t2-t1)+" milliseconds)");

}

private static int countingInversions(int[] a) {

int n = a.length;

int[] buf = new int[n];

int cnt = count(a,0,n-1,buf);

return cnt;

}

private static int count(int[] a, int s, int e, int[] buf){

if((e-s)<1) {

return 0;

}

int m = (s+e) / 2;

int leftCount = count(a,s,m,buf);

int rightCount = count(a,m+1,e,buf);

int mergeCount = merge(a,s,m,e,buf);

System.arraycopy(buf, s, a, s, (e-s)+1);

return leftCount + rightCount + mergeCount;

}

private static int merge(int[]a,int s, int m, int e, int[] buf){

//System.out.println("merge("+s+" "+e+")");

int left=s;

int right=m+1;

int count=0;

for(int k=s;k<=e;k++){

if(left<=m && ( (right>e) || (a[left] <= a[right]) ) ){

buf[k] = a[left++];

}else{

buf[k] = a[right++];

count = count + (m-left+1);

}

}

return count;

}