#include <bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second
typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;
const db EPS = 1e-9;
const db INF = 1e47;
vector<pair<db, LL>> compress(vector<pair<db, LL>> vec)
{
sort(ALL(vec));
vector<pair<db, LL>> res;
for (auto [p, c] : vec)
{
if (res.empty() || abs(res.back().F - p) > EPS)
{
res.PB({p, c});
}
else
{
res.back().S += c;
}
}
return res;
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout << fixed << setprecision(15);
int n;
cin >> n;
vector<pair<db, LL>> vec(n);
for (auto& [p, c] : vec)
cin >> p >> c;
vec = compress(vec);
n = SZ(vec);
for (auto [p, c] : vec)
cout << p << " " << c << "\n";
cout << "-----\n";
vector<LL> sx[2];
vector<db> sxx[2];
FOR(j, 0, 2)
{
sx[j].resize(n + 1);
sxx[j].resize(n + 1);
FOR(i, 0, n)
{
auto& [p, c] = vec[i];
sx[j][i + 1] = sx[j][i] + c;
db x = abs(1 - p) < EPS ? INF : 1 / (1 - p);
sxx[j][i + 1] = sx[j][i] * x;
p = 1 - p;
}
reverse(ALL(vec));
}
reverse(ALL(sx[1]));
reverse(ALL(sxx[1]));
FOR(k, 0, 2)
{
FOR(i, 0, n + 1)
{
cout << sx[k][i] << " ";
}
cout << endl;
FOR(i, 0, n + 1)
{
cout << sxx[k][i] << " ";
}
cout << endl;
}
db ans = 0;
FOR(k, 0, 2)
{
FOR(j, 0, n + 1)
{
int i = lower_bound(ALL(sxx[k]), sxx[k ^ 1][j]) - sxx[k].begin() - 1;
i = min(i, j);
if (i >= 0)
{
ans = max(ans, sx[k][i] + sx[k ^ 1][j] - sxx[k ^ 1][j]);
}
}
FOR(l, 0, 2)
{
reverse(ALL(sx[l]));
reverse(ALL(sxx[l]));
}
}
cout << ans << "\n";
return 0;
}
0.000000000000000 10
1.000000000000000 15
-----
0 10 25
0.000000000000000 0.000000000000000 1000000000000000043845843045076197354634047651840.000000000000000
25 15 0
1499999999999999984639126153007614336162066333696.000000000000000 0.000000000000000 0.000000000000000
0.000000000000000