> #include<iostream>
> #define N 5000
> using namespace std;
> 
> int a[N],b[N];
> 
> void MergeSort(int left,int right,__int64 &count)
> {
> 	if(left<right)
> 	{
> 		int mid=(left+right)/2;
> 		MergeSort(left,mid,count);
> 		MergeSort(mid+1,right,count);
> 		int i=left,j=mid+1,k=left;
> 		while(i<=mid&&j<=right)
> 			if(a[i]<a[j]) b[k++]=a[i++];
> 			else 
> 			{
> 				count=count+mid-i+1;
> 				b[k++]=a[j++];
> 			}
> 			while(i<=mid)
> 				b[k++]=a[i++];
> 			while(j<=right)
> 				b[k++]=a[j++];
> 			for(i=left;i<=right;i++)
> 				a[i]=b[i];
> 	}
> }
> 
> int main()
> {
> 	int i,n;
> 	__int64 count;
> 	cin>>n;
> 	while(n)
> 	{
> 		for(i=0;i<n;i++)
> 			cin>>a[i];
> 		count=0;
> 		MergeSort(0,n-1,count);
>         printf("%I64d\n",count);
> 		cin>>n;
> 	}
> 	return 0;
> }