#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N =  1E5+9;
int a[N],temp[N];
ll ans;

ll meger(int q[],int l,int r){



    if(l>=r) return 0;
    int mid = (l+r)>>1,k=0;
    int i = l,j = mid+1;
    ans = meger(q,l,mid)+meger(q,mid+1,r);


    while(i<=mid&&j<=r){
        if(q[i]<=q[j])  temp[k++] = q[i++];
        else {
            ans += mid -i+1;
            temp[k++] = q[j++];
        }
    }

    while(i<=mid)  temp[k++] = q[i++];
    while(j<=r) temp[k++] = q[j++];

    for(int i = l,j=0;i<=r;j++,i++)  q[i] = temp[j];

    return ans;
}

int main(){
    int n;
    cin>>n;
    for(int i = 0;i<n;i++) cin>>a[i];

    cout<<meger(a,0,n-1)<<endl;


    return 0;
}