#include <stdio.h>

#define MAX 200000
#define SENTINEL 2000000000
typedef long long ll;

int L[MAX / 2 + 2], R[MAX / 2 + 2];

ll merge(int A[], int n, int left, int mid, int right)
{
    int i, j, k;
    ll cnt = 0;
    int n1 = mid - left;
    int n2 = right - mid;
    for ( i = 0; i < n1; i++ ) {
        L[i] = A[left + i];
    }
    for ( i = 0; i < n2; i++ ) {
        R[i] = A[mid + i];
    }
    L[n1] = SENTINEL;
    R[n2] = SENTINEL;
    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];
            j++;
            cnt += n1 - i;
        }
    }
    return cnt;
}

ll mergeSort(int A[], int n, int left, int right)
{
    int mid;
    ll v1, v2, v3;
    if ( left + 1 < right ) {
        mid = (left + right) / 2;
        v1 = mergeSort(A, n, left, mid);
        v2 = mergeSort(A, n, mid, right);
        v3 = merge(A, n, left, mid, right);
        return v1 + v2 + v3;
    }
    return 0;
}

int main(void)
{
    int A[MAX], n, i;

    scanf("%d", &n);
    for ( i = 0; i < n; i++ ) {
        scanf("%d", &A[i]);
    }

    ll ans = mergeSort(A, n, 0, n);

    printf("%lld\n", ans);

    return 0;
}
