#include<stdio.h>
#define MAX 200000
#define SENTINEL 2000000000

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

int merge(int A[], int n, int left, int mid, int right){
    int i,j,k;
    int cnt = 0;
    int n1 = mid - left;
    int n2 = right - mid;
    
    for(i=0; i<n1; i++) L[i]=A[left+1];
    for(i=0; i<n2; i++) R[i]=A[mid+1];
    
    L[n1]=R[n2]=SENTINEL;
    i=j=0;
    for(k=left; k<right; k++){
        if(L[i] <= R[j]) {
            A[k]=L[i++];
        }else {
            A[k]=R[j++];
            cnt += n1 - i;
        }
    }
    return cnt;
}

int mergeSort(int A[], int n, int left, int right){
    int mid;
    int 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;
    }else return  0;
}

int main(){
    int A[MAX],n,i;
    
    scanf("%d",&n);
    for(i=0; i<n; i++){
        scanf("%d",&A[i]);
    }
    
    int ans = mergeSort(A, n, 0, n);
    printf("%d\n",ans);
    
    return 0;
}
