# include <iostream> # include <cmath> using namespace std; long long px(long long x,long long n,long long now){ if (now == n) return pow(-1,n-1)*pow(x,n); return pow(-1,now-1)*pow(x,now)+px(x,n,now+1); }int main(){ long long x,n; cin >> x >> n; printf("%lld",px(x,n,1)); cout << ".00"; return 0; }