import core.thread; import std.conv, std.stdio, std.string; import std.algorithm, std.array, std.bigint, std.container, std.math, std.range, std.regex; // Input class EOFException : Throwable { this() { super("EOF"); } } string[] tokens; string readToken() { for (; tokens.empty; ) { tokens = readln.split; if (tokens.empty && stdin.eof) throw new EOFException; } auto token = tokens[0]; tokens.popFront; return token; } int readInt() { return to!int(readToken); } long readLong() { return to!long(readToken); } real readReal() { return to!real(readToken); } // chmin/chmax void chmin(T)(ref T t, in T f) { if (t > f) t = f; } void chmax(T)(ref T t, in T f) { if (t < f) t = f; } // Pair struct Pair(S, T) { S x; T y; int opCmp( const Pair p) const { return (x < p.x) ? -1 : (x > p.x) ? +1 : (y < p.y) ? -1 : (y > p.y) ? +1 : 0; } int opCmp(ref const Pair p) const { return (x < p.x) ? -1 : (x > p.x) ? +1 : (y < p.y) ? -1 : (y > p.y) ? +1 : 0; } string toString() const { return "(" ~ to!string(x) ~ ", " ~ to!string(y) ~ ")"; } } auto pair(S, T)(inout(S) x, inout(T) y) { return Pair!(S, T)(x, y); } // Array int binarySearch(T)(in T[] as, in bool delegate(T) test) { int low = -1, upp = as.length; for (; low + 1 < upp; ) { int mid = (low + upp) >> 1; (test(as[mid]) ? low : upp) = mid; } return upp; } int lowerBound(T)(in T[] as, in T val) { return as.binarySearch((T a) { return (a < val); }); } int upperBound(T)(in T[] as, in T val) { return as.binarySearch((T a) { return (a <= val); }); } T[] unique(T)(in T[] as) { T[] bs; foreach (a; as) if (bs.empty || bs[$ - 1] != a) bs ~= a; return bs; } int N; real P; void main(string[] args) { try { for (; ; ) { N = readInt; P = readReal; int[] cnt = new int[N + 1]; foreach (x; 2 .. N + 1) { for (int y = 2 * x; y <= N; y += x) { ++cnt[y]; } } int[] cntCnt = new int[cnt.reduce!max + 1]; foreach (x; 2 .. N + 1) { ++cntCnt[cnt[x]]; } real ans = 0.0; real prob = 1.0; foreach (c; cntCnt) { ans += c * prob; prob *= (1.0 - P); } writeln(ans); } } catch (EOFException) {} }