li n, k;

bool read() {
	return !!(cin >> n >> k);
}

void solve() {
	cout << (n / k + 1) * k << endl;
}

int y;

bool read() {
	return !!(cin >> y);
}

bool leap(int y) {
	return y % 400 == 0 || (y % 4 == 0 && y % 100 != 0);
}

void solve() {
	bool is_leap = leap(y);
	int d = 0;
	do {
		d++;
		if (leap(y)) d++;
		y++;
		d %= 7;
	} while (d || leap(y) != is_leap);
	cout << y << endl;
}

li n, a, b, p, q;

bool read() {
	return !!(cin >> n >> a >> b >> p >> q);
}

li gcd(li a, li b) { return !a ? b : gcd(b % a, a); }
li lcm(li a, li b) { return a / gcd(a, b) * b; }

void solve() {
	li ans = 0;
	ans += (n / a) * p;
	ans += (n / b) * q;
	ans -= (n / lcm(a, b)) * min(p, q);
	cout << ans << endl;
}

const int N = 20, EXPN = (1 << 18) + 3;

int n;
ld p[N][N];

bool read() {
	if (!(cin >> n)) return false;
	forn(i, n) forn(j, n) assert(cin >> p[i][j]);
	return true;
}

ld z[EXPN][N];

ld solve(int mask, int i) {
	ld& ans = z[mask][i];
	if (ans > -0.5) return ans;
	if (mask == (1 << n) - 1) return ans = !i;
	ans = 0;
	forn(j, n)
		if (!(mask & (1 << j))) {
			ld cur = 0;
			cur += solve(mask | (1 << j), i) * p[i][j];
			cur += solve(mask | (1 << j), j) * p[j][i];
			ans = max(ans, cur);
		}
	return ans;
}

void solve() {
	if (n == 1) {
		puts("1");
		return;
	}

	forn(i, 1 << n) forn(j, n) z[i][j] = -1;

	ld ans = 0;
	forn(i, n)
		forn(j, i) {
			int mask = (1 << i) | (1 << j);
			ld cur = 0;
			cur += solve(mask, i) * p[i][j];
			cur += solve(mask, j) * p[j][i];
			ans = max(ans, cur);
		}
	cout << ans << endl;
}