#include <iostream>#include<cstdio>#include<cstring>#include<cstdlib>#include<cstring>#include<algorithm>#define MAX 500010#define LL long longusing namespace std;int num[MAX],tree[MAX];int n;LL ans=0;struct node{ int value,sum;};node arr[MAX];int lowbit(int value){ return value&(-value);}void build(int value){ while(value<=n){ tree[value]+=1; value+=lowbit(value); }}int Get_sum(int value){ int result=0; for(int i=value;i>=1;i-=lowbit(i)) { result+=tree[i]; } return result;}bool cmp(node n1,node n2){ return n1.value<n2.value;}int main(){ while(scanf("%d",&n)==1 && n) { ans=0; memset(tree,0,sizeof(tree)); for(int i=1;i<=n;i++) scanf("%d",&arr[i].value),arr[i].sum=i; sort(arr+1,arr+n+1,cmp); for(int i=1;i<=n;i++) { num[arr[i].sum]=i; } for(int i=1;i<=n;i++) { build(num[i]); ans+=i-Get_sum(num[i]); } printf("%I64dn",ans); } return 0;}
