#include <iostream>

#include <vector>

#include <algorithm>

#include <math.h>

#include <iomanip>

using namespace std;

struct point

{

	double x;

	double y;

};

int N;

double dis;

vector<point> V;

static auto fast_io = []

{

	ios::sync_with_stdio(false);

	cout.tie(nullptr);

	cin.tie(nullptr);

	return 0;

}();

void read()

{

	double a, b;

	V.clear();

	for (int i = 0; i < N; ++i) cin >> a >> b, V.push_back({ a, b });

}

double ds(point& a, point& b)

{

	return sqrt(pow(a.x - b.x, 2) + pow(a.y - b.y, 2));

}

double Combine(int& a, int& b, int& mid, double& l, double& r)

{

	double d = min(l, r);

	double line = (V[mid].x + V[mid + 1].x) / 2;

	double Min = d;

	for (int i = mid + 1; i <= b && V[i].x < line + d; ++i)

		for (int j = mid; j >= a && V[j].x > line - d; --j)

			Min = min(Min, ds(V[i], V[j]));

	return Min;

}

double Divide(int a, int b)

{

	if (a >= b) return 10000;

	int mid = (a + b) / 2;

	double l = Divide(a, mid);

	double r = Divide(mid + 1, b);

	return Combine(a, b, mid, l, r);

}

void print()

{

	if (dis < 10000) cout << setprecision(4) << fixed << dis << "\n";

	else cout << "INFINITY\n";

}

int main()

{

	while (cin >> N, N)

	{

		read();

		sort(V.begin(), V.end(), [](point& a, point& b) { return a.x < b.x; });

		dis = Divide(0, N - 1);

		print();		

	}

}