#pragma GCC optimize(3)

 #include<bits/stdc++.h>

 #define pa pair<ll,ll>

 #define CLR(a,x) memset(a,x,sizeof(a))

 using namespace std;

 typedef long long ll;

 const int maxn=;

 inline char gc(){

     return getchar();

     static const int maxs=<<;static char buf[maxs],*p1=buf,*p2=buf;

     return p1==p2&&(p2=(p1=buf)+fread(buf,,maxs,stdin),p1==p2)?EOF:*p1++;

 }

 inline ll rd(){

     ll x=;char c=gc();bool neg=;

     while(c<''||c>''){if(c=='-') neg=;c=gc();}

     while(c>=''&&c<='') x=(x<<)+(x<<)+c-'',c=gc();

     return neg?(~x+):x;

 }

 int N,a[maxn];

 int tr[maxn];

 inline int lowbit(int x){return x&(-x);}

 inline void add(int x,int y){

     for(;x<=N;x+=lowbit(x)) tr[x]+=y;

 }

 inline int query(int x){

     int re=;for(;x;x-=lowbit(x)) re+=tr[x];return re;

 }

 int main(){

     //freopen("","r",stdin);

     int i,j,k;

     N=rd();

     for(i=;i<=N;i++) a[i]=rd();

     int num=;

     for(i=;i<=N;i++){

         num+=i--query(a[i]);

         add(a[i],);

     }

     printf("%d\n",*(num/)+(num&));

     return ;

 }