#include <iostream> #include <algorithm> #include <cstdio> using namespace std; int n,a,b; int x[25]; int xx[25]; int main(){ cin>>n>>a>>b; bool haha=1; for(int i=1;i<=n;i++){ cin>>x[i]; xx[i]=x[i]; if(x[i]!=i) haha=0; } if(haha) cout<<"0.00000000000000000000"<<endl; else{ int cnt=0; sort(xx+1,xx+n+1); for(int i=1;i<=n;i++){ if(xx[i]!=x[i]) cnt++; } if(cnt%2==0){ cnt=cnt/2; } else{ cnt=cnt/2+1; } double c=cnt*a*1.0; double d=b*n*1.0; c=min(c,d); printf("%.20f",c); } return 0; }