#include
     
      #include
      
       using namespace std;typedef long long ll;#define N 500010ll a[N],b[N];ll n,ans;void merge_sort(ll x,ll y){    if (y-x>1)    {        ll m=x+(y-x)/2;        ll  p=x,q=m,i=x;        merge_sort(x,m);        merge_sort(m,y);       while (p
       
        
         =y||(p
         
          <=a[q]))            b[i++]=a[p++];           else           {               if (p
          
           >n&&n!=0) { ans=0; for (ll i=0;i
           
            >a[i]; merge_sort(0,n); cout << ans << endl; } return 0;}