include[HTML_REMOVED]
using namespace std;
typedef long long LL;
const int N=1e5+10;
int a[N],tmp[N];
LL merge_sort(int q[],int l,int r){
if(l>=r) return 0;
int mid=l+r>>1;
LL res=merge_sort(q,l,mid)+merge_sort(q,mid+1,r);
int k=0,i=l,j=mid+1;
while(i<=mid&&j<=r){
if(q[i]<=q[j]) tmp[k++]=q[i++];
else {
res+=mid-i+1;
tmp[k++]=q[j++];
}
while(i<=mid) tmp[k++]=q[i++];
while(j<=r) tmp[k++]=q[j++];
for(i=l,j=0;i<=r;i++,j++) q[i]=tmp[j];
return res;
}
}
int main(){
int n;
scanf(“%d”,&n);
for(int i=0;i<n;i++) scanf(“%d”,&a[i]);
cout<<merge_sort(a,0,n-1)<<endl;
return 0;
}