#define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long double ld; typedef long long ll; typedef vector vint; typedef vector vll; typedef pair pii; typedef pair pll; typedef pair pdd; typedef complex compd; #define quickIO() {cin.tie(0); cout.sync_with_stdio(false);} #define reach(i,a) for(auto i:a) #define rep(i,n) for(int i=0;i<((int)n);i++) #define REP(i,n) for(int i=0;i<=((int)n);i++) #define srep(i,a,n) for(int i=a;i<((int)n);i++) #define SREP(i,a,n) for(int i=a;i<=((int)n);i++) #define rrep(i,n) for(int i=n-1;i>=0;i--) #define RREP(i,n) for(int i=n;i>=0;i--) #define all(a) (a).begin(),(a).end() #define mp(a,b) make_pair(a,b) #define mt make_tuple #define pb push_back template istream& operator >> (istream& is, vector& vec) { for (T& x : vec) is >> x; return is; } template ostream& operator << (ostream& os, vector& vec) { os << "["; rep(i, vec.size()) os << (i ? ", " : "") << vec[i]; os << "]"; return os; } template istream& operator >> (istream& is, pair& p) { is >> p.first >> p.second; return is; } template ostream& operator << (ostream& os, pair& p) { os << "(" << p.first << ", " << p.second << ")"; return os; } int bitcnt(ll x) { x = ((x & 0xAAAAAAAAAAAAAAAA) >> 1) + (x & 0x5555555555555555); x = ((x & 0xCCCCCCCCCCCCCCCC) >> 2) + (x & 0x3333333333333333); x = ((x & 0xF0F0F0F0F0F0F0F0) >> 4) + (x & 0x0F0F0F0F0F0F0F0F); x = ((x & 0xFF00FF00FF00FF00) >> 8) + (x & 0x00FF00FF00FF00FF); x = ((x & 0xFFFF0000FFFF0000) >> 16) + (x & 0x0000FFFF0000FFFF); x = ((x & 0xFFFFFFFF00000000) >> 32) + (x & 0x00000000FFFFFFFF); return x; } int bitcnt(int x) { x = ((x & 0xAAAAAAAA) >> 1) + (x & 0x55555555); x = ((x & 0xCCCCCCCC) >> 2) + (x & 0x33333333); x = ((x & 0xF0F0F0F0) >> 4) + (x & 0x0F0F0F0F); x = ((x & 0xFF00FF00) >> 8) + (x & 0x00FF00FF); x = ((x & 0xFFFF0000) >> 16) + (x & 0x0000FFFF); return x; } ll sqrtll(ll x) { ll left = 0, right = x; rep(i, 100) { ll mid = (left + right) >> 1; if (mid*mid <= x) left = mid; else right = mid; } return left; } ll gcd(ll a, ll b) { return b == 0 ? a : gcd(b, a%b); } #define debug(x) printf("Case #%d: ", x) #define DEBUG 0 const ll inf = 1e9; const ld infl = 1e100; const ll mod = 1e9 + 7; const ld eps = 1e-9; const int dx[] = { 1,0,-1,0,0 }; const int dy[] = { 0,1,0,-1,0 }; int main() { int n; cin >> n; ld p, q; cin >> p >> q; if (p == 1) { cout << 1 << endl; return 0; } ld ret = p; srep(i, 1, n) { ret = p + q * q * ret / (1 - p * ret); } printf("%.18Lf\n", ret); return 0; }