#include<bits/stdc++.h>using namespace std;class BearCheats{public:string eyesight(int A, int B){int digA[42],digB[42];int t = 0;while(A){digA[t++] = A%10;A/=10;}for(int i = 0; i < t; i++){digB[i] = B%10;B/=10;}int dif = 0;for(int i = 0; i < t; i++){if(digA[i]!=digB[i]) dif++;}if(dif<=1) return "happy";else return "glasses";}};

#include<bits/stdc++.h>
using namespace std;
const int maxn = 501;bool vis[maxn][maxn];bool dfs(int *dat)
{if(dat[0] == dat[1] && dat[1] == dat[2]) return true;int ndat[3]= {dat[0]<<1,dat[1]-dat[0],dat[2]};sort(ndat,ndat+3);if(!vis[ndat[0]][ndat[1]] && ( vis[ndat[0]][ndat[1]] = true,dfs(ndat))) return true;ndat[0] = dat[0]<<1; ndat[1] = dat[1]; ndat[2] = dat[2] - dat[0];sort(ndat,ndat+3);if(!vis[ndat[0]][ndat[1]] && ( vis[ndat[0]][ndat[1]] = true,dfs(ndat))) return true;ndat[0] = dat[0]; ndat[1] = dat[1]<<1; ndat[2] = dat[2] - dat[1];sort(ndat,ndat+3);if(!vis[ndat[0]][ndat[1]] && ( vis[ndat[0]][ndat[1]] = true,dfs(ndat))) return true;return false;
}class BearPlaysDiv2{
public:string equalPiles(int A, int B, int C){if( (A+B+C)/3*3 != A+B+C ) return "impossible";int dat[3] = {A,B,C};sort(dat,dat+3);vis[dat[0]][dat[1]] = true;if(dfs(dat)) return "possible";else return "impossible";}
};

#include<bits/stdc++.h>
using namespace std;
const int maxn = 550;
int a[maxn];
int t[maxn];
const double onecmp = log(0.5);
int times;
void merge_sort(int* a,int l,int r)
{if(r-l<=1) return ;int mid = (l+r)>>1;merge_sort(a,l,mid);merge_sort(a,mid,r);int i = l, j = mid, k =l,p;while(i < mid && j < r){if(times++,a[i]>=a[j]) t[k] = a[j++];else t[k] = a[i++];k++;}if(i == mid) for(p = j; p < r; p++) t[k++] = a[p];else for(p = i; p < mid; p++) t[k++] = a[p];for(k = l;k < r; k++) a[k] = t[k];
}class BearSortsDiv2{
public:double getProbability(vector <int> seq){for(int i = 0; i < seq.size(); i++){a[seq[i]-1] = i;}times = 0;merge_sort(a,0,seq.size());//log(ans);double ans =return times*onecmp;}
}Bear;
/*
int main()
{freopen("in.txt","r",stdin);vector<int> s;int tmp;while(~scanf("%d",&tmp))s.push_back(tmp);double ans = Bear.getProbability(s);printf("%lf",ans);return 0;
}
*/