#include <bits/stdc++.h>
#define int long long
#define double long double
using namespace std;
const int MAX = 300000;
const int CONST = 100000;
const int INF = 0x3f3f3f3f3f3f3f3f;
struct Line {
double A, B;
int idx;
double get(double X) { return A * X + B; }
Line() : A(0), B(0), idx(0) {}
Line(double A, double B, int idx) : A(A), B(B), idx(idx) {}
};
struct Node {
double s, e, l = -1, r = -1;
Line line;
Node(double s, double e, Line line) : s(s), e(e), line(line) {}
};
vector<Node> tree;
void update(int n, Line v) {
double s = tree[n].s, e = tree[n].e, m = (s + e) / 2;
Line low = tree[n].line, high = v;
if (low.get(s) < high.get(s))
swap(low, high);
if (low.get(e) >= high.get(e)) {
tree[n].line = low;
return;
}
if (low.get(m) > high.get(m)) {
tree[n].line = low;
if (tree[n].r == -1) {
tree[n].r = tree.size();
tree.push_back(Node(m, e, Line(0, 0, 0)));
}
update(tree[n].r, high);
} else {
tree[n].line = high;
if (tree[n].l == -1) {
tree[n].l = tree.size();
tree.push_back(Node(s, m, Line(0, 0, 0)));
}
update(tree[n].l, low);
}
}
Line max(Line X, Line Y, int V) { return X.get(V) > Y.get(V) ? X : Y; }
Line query(int n, int v) {
if (n == -1)
return Line(0, 0, 0);
int s = tree[n].s, e = tree[n].e, m = (s + e) / 2;
if (v <= m)
return max(tree[n].line, query(tree[n].l, v), v);
return max(tree[n].line, query(tree[n].r, v), v);
}
double dp[MAX][2];
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
int N, K, st, en, md;
double ans;
Line V;
cin >> N >> K;
st = 0, en = ans = N * CONST;
while (st <= en) {
md = st + en >> 1, tree.clear();
tree.push_back(Node(0, CONST, Line(0, 0, 0)));
for (int i = 1; i <= N; i++) {
V = query(0, (double)CONST / i);
dp[i][0] = CONST + V.get((double)CONST / i) - md, dp[i][1] = V.idx + 1;
update(0, Line(-i, dp[i][0], dp[i][1]));
}
ans = min(ans, dp[N][0] + md * K);
if (dp[N][1] <= K)
en = md - 1;
else
st = md + 1;
}
cout << fixed << setprecision(8) << (double)ans / CONST << '\n';
return 0;
}
