#include #define syosu(x) fixed< P; typedef pair pdd; typedef pair pll; typedef vector vi; typedef vector vvi; typedef vector vd; typedef vector vvd; typedef vector vl; typedef vector vvl; typedef vector vs; typedef vector

vp; typedef vector vvp; typedef vector vpll; typedef pair pip; typedef vector vip; const int inf=1<<30; const ll INF=1ll<<60; const double pi=acos(-1); const double eps=1e-8; const ull mod=1e9+7; const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1}; int n; double a[101]; int main(){ cin>>n; a[0]=4,a[1]=3; for(int i=2;i<=n;i++){ a[i]=(19*a[i-1]-12*a[i-2])/4; } cout<