#include<bits/stdc++.h>
using namespace std;
int number[500005];
int copy_array[5000005];
long long int ans=0;
int total;
//int read(){
//	int acc=0,sign=1;
//	char ch=getchar();
//	while(ch<'0'&&ch>'9'){
//		if(ch=='-'){
//			sign=-1;
//			ch=getchar();
//		}	
//	}
//	while(ch>='0'&&ch<='9'){
//		acc=acc*10+ch-'0';
//		ch=getchar();
//	}
//	return acc*sign;
//}
void msort(int left,int right){
	printf("%d,%d\n",left,right);
	if(left==right)
		return;
	int mid=(left+right)/2;
	int reme_left=left;
	int reme_right=mid+1;
	int array_start=left;
	msort(1,mid);
	msort(mid+1,right);
	while(reme_left<=mid&&reme_right<=right){
		if(number[reme_left]<=number[reme_right])
			copy_array[array_start++]=number[reme_left++];
		else{
			copy_array[array_start++]=number[reme_right++];
			ans+=mid-reme_left+1;
		}
	}
	while(reme_left<=mid)
		copy_array[array_start++]=number[reme_left++];
	while(reme_right<=right)
		copy_array[array_start++]=number[reme_right++];
	for(int m=left;m<=right;m++)
		number[m]=copy_array[m];
}
int main()
{
	//freopen("test.txt","r",stdin);
	scanf("%d",&total);
	for(int m=1;m<=total;m++){
		scanf("%d",&number[m]);
	}
	msort(1,total);
	printf("%lld",ans);
	return 0;
}