#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // C++ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include //#include //#include #define rep(i,j,k) for(int i=(int)j;i<(int)k;i++) #define ll long long #define Sort(v) sort(all(v)) #define INF 1000000000 #define END return 0 #define pb push_back #define se second #define fi first #define pb push_back #define all(v) (v).begin() , (v).end() #define MP make_pair #define MOD 1000000007LL; using namespace std; int day[12]={31,28,31,30,31,30,31,31,30,31,30,31}; int main (){ ll n,b; cin>>n>>b; vector v(n); rep(i,0,n)cin>>v[i]; double ans1=0; rep(i,0,n){ ans1+=v[i]*pow(b,v[i]-1); } double ans2=0; rep(i,0,n){ if(v[i]!=-1.0)ans2+=1.0/(v[i]+1)*pow(b,v[i]+1); else ans2+=log(b); } cout<