#pragma GCC optimize("Ofast")
//#pragma GCC target ("sse4")

#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
#include<array>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acosl(-1.0);

ll mod_pow(ll x, ll n, ll m = mod) {
	if (n < 0) {
		ll res = mod_pow(x, -n, m);
		return mod_pow(res, m - 2, m);
	}
	if (abs(x) >= m)x %= m;
	if (x < 0)x += m;
	ll res = 1;
	while (n) {
		if (n & 1)res = res * x % m;
		x = x * x % m; n >>= 1;
	}
	return res;
}
struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n % mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, ll n) {
	if (n == 0)return modint(1);
	modint res = (a * a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
modint operator/=(modint& a, modint b) { a = a / b; return a; }
const int max_n = 1 << 20;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
modint combP(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[a - b];
}

void solve() {
	int n; cin >> n;
	int ans = mod;
	rep(i, n) {
		int a, p, x; cin >> a >> p >> x;
		if (a < x) {
			ans = min(ans, p);
		}
	}
	if (ans == mod)ans = -1;
	cout << ans << "\n";
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout << fixed << setprecision(5);
	//init_f();
	//init();
	//expr();
	//int t; cin >> t; rep(i,t)
	solve();
	return 0;
}
#include <vector>
#include <stack>
#include <queue>
#include <list>
#include <bitset>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <algorithm>
#include <numeric>
#include <iostream>
#include <iomanip>
#include <string>
#include <chrono>
#include <random>
#include <cmath>
#include <cassert>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <functional>
#include <sstream>

using namespace std;


class DisjointSet {
    public:
        DisjointSet(int n) : N(n), sz(n), pars(n, -1) {
        }
        void reset() { sz = N, fill(pars.begin(), pars.end(), -1); }
        int find(int x) { return pars[x] < 0 ? x : pars[x] = find(pars[x]); }
        int size() { return sz; }
        int count(int x) { return -pars[find(x)]; }
        bool unite(int x, int y) {
            x = find(x), y = find(y);
            if (x == y) { return false; }
            --sz;
            if (pars[x] < pars[y]) { swap(x, y); }
            pars[y] += pars[x];
            pars[x] = y;
            return true;
        }
    private:
        int N, sz;
        vector<int> pars;
};

int main(int argc, char** argv) {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(12);

    int n;
    cin >> n;

    vector<int> X(n);
    vector<int> Y(n);
    for (int i = 0; i < n; ++i) {
        cin >> X[i] >> Y[i];
    }

    long double eps = 1e-9;

    long double lo = 0, hi = 100;
    int rnd = 150;

    DisjointSet ds(n + 2);
    int s = n, t = n + 1;

    auto ok = [&](long double r) {
        ds.reset();
        for (int i = 0; i < n; ++i) {
            if (Y[i] - 2 * r - (-100) < eps) {
                ds.unite(i, s);
            }
            if (100 - (Y[i] + 2 * r) < eps) {
                ds.unite(i, t);
            }
        }

        for (int i = 0; i < n; ++i) {
            for (int j = i + 1; j < n; ++j) {
                auto d = hypot(X[i] - X[j], Y[i] - Y[j]);
                if (d <= 2 * r + eps) {
                    ds.unite(i, j);
                }
            }
        }
        return ds.find(s) != ds.find(t);
    };

    while (rnd-- > 0) {
        auto mi = (lo + hi) / 2;
        if (ok(mi)) {
            lo = mi;
        } else {
            hi = mi;
        }
    }
    cout << lo << '\n';
    return 0;
}