#include <bits/stdc++.h>
using namespace std;
const int inf = (int)1e9;
const int mod = inf + 7;
const double eps = 1e-9;
int n, m;
double dp[100100];
bool was[100100];
double binpow(double a, int k) {
  if (k == 0) return 1;
  double res = binpow(a, k / 2);
  res = res * res;
  if (k % 2) res = res * a;
  return res;
}
double calc(int k) {
  if (was[k]) return dp[k];
  was[k] = 1;
  double &res = dp[k];
  res = 0;
  res += binpow(k / (1.0 * m), n);
  return res;
}
double solve(int k) { return calc(k) - calc(k - 1); }
int main() {
  cin >> m >> n;
  double ans = 0;
  for (int i = 1; i <= m; i++) {
    ans += solve(i) * i;
  }
  printf("%.7lf\n", ans);
  return 0;
}
