#include <iostream>#include <cstdio>#include <sstream>#include <cstring>#include <string>#include <cmath>#include <vector>#include <queue>#include <stack>#include <map>#include <set>#include <list>#include <algorithm>#include <functional>#define sz(v) ((int)(v).size())#define rep(i, n) for(int i = 0; i < n; i++)#define repf(i, a, b) for(int i = a; i <= b; i++)#define repd(i, a, b) for(int i = a; i >= b; i--)#define out(n) printf("%dn", n)#define mset(a, b) memset(a, b, sizeof(a)using namespace std;typedef long long lint;const int INF = 1 << 30;const int MaxN = 100005;int c[22][22];double f[2][22];int n;double p;void get_c(){ repf(i, 1, 21) { c[i][0] = 1; repf(j, 1, i - 1) { c[i][j] = c[i - 1][j - 1] + c[i - 1][j]; } c[i][i] = 1; }}double mypow(double x, int y){ double res = 1.0; repf(i, 1, y) res *= x; return res;}int main(){ get_c(); while(2 == scanf("%d%lf", &n, &p)) { repf(i, 1, n) { f[0][i] = 0.0; repf(j, 1, i - 1) { f[0][i] += c[i - 1][i - j] * f[1][j] * mypow(mypow((1 - p), j), i - j); } f[1][i] = 1 - f[0][i]; } printf("%.8lf", f[1][n]); } return 0;}
