#include <bits/stdc++.h>
typedef long long  ll;
using namespace std;
#define islld 1
const double INF = 1e9;
const double EPS = 1e-5;
const double PI = acos(-1);
 
template<class T>
class Point
{
public:
    union
    {
        struct
        {
            T x,y;
        };
        T data[2];
    };
    Point():x(0),y(0){}
    Point(T x,T y):x(x),y(y)
    {
 
    }
    Point(T s):x(s),y(s){}
    template<typename T1>
    Point(const Point<T1>& p):x(p.x),y(p.y){}
 
    void readInt32(){
        scanf("%d%d",&x,&y);
    }
    void readInt64(){
#if islld
        scanf("%lld%lld",&x,&y);
#else
        scanf("%I64d%I64d",&x,&y);
#endif
    }
    void readfloat(){
        scanf("%f%f",&x,&y);
    }
    void readLongDouble(){
        scanf("%Lf%Lf",&x,&y);
    }
    void readDouble(){
        scanf("%lf%lf",&x,&y);
    }
    template<typename T1>
    bool operator==(const Point<T1>& rhs)
    {
        auto v = *this-rhs;
        return fabs(v.x) <= EPS && fabs(v.y) <= EPS;
    }
    inline friend Point operator+(const Point& lhs, const Point& rhs) { return Point(lhs.x+rhs.x,lhs.y+rhs.y); }
    inline friend Point operator-(const Point& lhs, const Point& rhs) { return Point(lhs.x-rhs.x,lhs.y-rhs.y); }
    inline friend Point operator*(const Point& lhs, const Point& rhs) { return Point(lhs.x*rhs.x,lhs.y*rhs.y); }
    inline friend Point operator/(const Point& lhs, const Point& rhs) { return Point(lhs.x/rhs.x,lhs.y/rhs.y); }
};
template<typename T>
inline T cross(const Point<T>& v1,const Point<T>& v2)
{
    return v1.x*v2.y-v1.y*v2.x;
}
template<typename T>
inline T dot(const Point<T>& v1,const Point<T>& v2)
{
    return v1.x*v2.x+v1.y*v2.y;
}
template<typename T>
inline T sqlen(const Point<T>& p)
{
    return p.x*p.x+p.y*p.y;
}
template<typename T>
struct cmp_x {
    bool operator()(const Point<T> & a, const Point<T> & b) {
        return a.x < b.x || a.x == b.x && a.y < b.y;
    }
};
template<typename T>
struct cmp_y {
    bool operator()(const Point<T> & a, const Point<T> & b)const {
        return a.y < b.y || a.y == b.y && a.x < b.x ;
    }
};
 
template<typename T>
pair<pair<Point<T>,Point<T>>,T> closest_pair(vector<Point<T>> & points)
{
    T d = INF;
    T ds = INF;
    Point<T> p1,p2;
    sort(points.begin(),points.end(),cmp_x<T>());
    set<Point<T>, cmp_y<T> > w;
    for(int i=0;i<points.size();i++){
        auto it = w.lower_bound(Point<ll>(-INF,points[i].y-ds));
        while(it != w.end() && abs(points[i].y-it->y) <= ds){
            auto itc = it;
            it++;
            if(abs(points[i].x - itc->x) > d){
                w.erase(itc);
            }
            else{
                T di = sqlen(points[i]-*itc);
                if(d > di){
                    d =di;
                    ds = sqrt(d)+1;
                    p1 = points[i];
                    p2 = *itc;
                }
            }
        }
        w.insert(points[i]);
    }
    return make_pair(make_pair(p1,p2),d);
}
 
int main()
{
   int n;
 
   vector<Point<double>> ps;
   while(true)
   {
       scanf("%d",&n);
       if(n==0)
        break;
       ps.clear();
       ps.reserve(n);
       for(int i=0;i<n;i++)
       {
           Point<double> p;p.readDouble();
           ps.push_back(p);
       }
       double ans = 10000;
       double d = closest_pair<double>(ps).second;
       ans = min(ans,sqrt((double)d));
       if(ans >= 10000.0-EPS)
        puts("INFINITY");
       else
        printf("%.4f\n",ans);
   }
   return 0;
}
 

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