#include<cmath>

#include<cstdio>

#include<algorithm>

#define eps 1e-12

#define MN 110001

#define ld long double

using namespace std;

int read_p,read_ca;

inline int read(){

    read_p=;read_ca=getchar();

    while(read_ca<''||read_ca>'') read_ca=getchar();

    while(read_ca>=''&&read_ca<='') read_p=read_p*+read_ca-,read_ca=getchar();

    return read_p;

}

struct po{ld x,y;};

struct na{po p;int n;}p[MN];

struct e{int x,y,ne,pre;}b[MN<<];

struct bi{int x,y;ld z;}B[MN<<];

bool operator < (bi a,bi b){return a.z<b.z;}

bool operator < (na a,na b){return a.p.x==b.p.x?a.p.y<b.p.y:a.p.x<b.p.x;}

int n,m,num=,l[MN],st[MN],top,NUM=,x,y,_l[MN],_num=,fa[MN];ld _A,_B;

inline void _add(int x,int y){b[++num].x=x;b[num].y=y;b[num].ne=l[x];b[l[x]].pre=num;l[x]=num;}

inline void add(int x,int y){_add(x,y);_add(y,x);}

inline void _del(int i){if(l[b[i].x]==i)l[b[i].x]=b[i].ne;else{b[b[i].pre].ne=b[i].ne;if(b[i].ne)b[b[i].ne].pre=b[i].pre;}}

inline void del(int i){_del(i);_del(i^);}

ld cha(po a,po b,po c){return (b.x-a.x)*(c.y-b.y)-(c.x-b.x)*(b.y-a.y);}

bool _cha(po a,po b,po c){return cha(a,b,c)<=;}

inline bool ju(po a,po b,po c,po d){return (_cha(a,b,c)^_cha(a,b,d))&&(_cha(c,d,a)^_cha(c,d,b));}

ld sqr(ld x){return x*x;}

inline ld min(ld a,ld b){return a<b?a:b;}

bool incir(po a,po b,po c,po d){

    ld m=(a.x*(b.y-c.y)+b.x*(c.y-a.y)+c.x*(a.y-b.y))*.;

    ld x=(sqr(a.x)*(b.y-c.y)+sqr(b.x)*(c.y-a.y)+sqr(c.x)*(a.y-b.y)-(a.y-b.y)*(b.y-c.y)*(c.y-a.y))/m;

    ld y=((a.x-b.x)*(b.x-c.x)*(c.x-a.x)-sqr(a.y)*(b.x-c.x)-sqr(b.y)*(c.x-a.x)-sqr(c.y)*(a.x-b.x))/m;

    return sqrt(sqr(x-a.x)+sqr(y-a.y))+eps>sqrt(sqr(x-d.x)+sqr(y-d.y));

}

void work(int L,int R){

    if (R-L<=){

        for (int i=L;i<R;i++)

        for (int j=i+;j<=R;j++) add(i,j);

        return;

    }

    int mid=L+R>>;

    work(L,mid);work(mid+,R);

    top=;

    for (int i=L;i<=R;st[++top]=i++)

    while (top>&&cha(p[st[top-]].p,p[st[top]].p,p[i].p)<) top--;

    int Ld,Rd,id;

    for (int i=;i<top;i++)

    if (st[i]<=mid&&st[i+]>mid) Ld=st[i],Rd=st[i+];

    add(Ld,Rd);

    for(;;){

        id=-;

        for (int i=l[Ld];i;i=b[i].ne)

        if (b[i].y!=Rd)

        if (cha(p[b[i].y].p,p[Ld].p,p[Rd].p)>&&(id==-||incir(p[Ld].p,p[Rd].p,p[id].p,p[b[i].y].p))) id=b[i].y;

        for (int i=l[Rd];i;i=b[i].ne)

        if (b[i].y!=Ld)

        if (cha(p[Ld].p,p[Rd].p,p[b[i].y].p)>&&(id==-||incir(p[Ld].p,p[Rd].p,p[id].p,p[b[i].y].p))) id=b[i].y;

        if (id==-) break;

        if (id<=mid){

            for (int i=l[Ld];i;i=b[i].ne)

            if (b[i].y!=Rd)

            if (ju(p[id].p,p[Rd].p,p[b[i].y].p,p[Ld].p)) del(i);

            Ld=id;

        }else{

            for (int i=l[Rd];i;i=b[i].ne)

            if (b[i].y!=Ld)

            if (ju(p[id].p,p[Ld].p,p[b[i].y].p,p[Rd].p)) del(i);

            Rd=id;

        }

        add(Ld,Rd);

    }

}

int gf(int x){return fa[x]==x?x:fa[x]=gf(fa[x]);}

int main(){

    //freopen("a.in","r",stdin);

    //freopen("a.out","w",stdout);

    register int i,j;

    n=read();scanf("%Lf%Lf",&_A,&_B);

    for (i=;i<n;i++) scanf("%Lf%Lf",&p[i].p.x,&p[i].p.y),p[i].n=i+,fa[i]=i;

    sort(p,p+n);

    work(,n-);

    for (i=;i<n;i++)

    for (j=l[i];j;j=b[j].ne) if (b[j].y>i) B[NUM].x=i,B[NUM].y=b[j].y,B[NUM++].z=sqrt(sqr(p[i].p.x-p[b[j].y].p.x)+sqr(p[i].p.y-p[b[j].y].p.y))/;

    for (i=;i<n;i++) B[NUM].x=i,B[NUM].y=n,B[NUM++].z=min(p[i].p.x,_B-p[i].p.y);

    for (i=;i<n;i++) B[NUM].x=i,B[NUM].y=n+,B[NUM++].z=min(_A-p[i].p.x,p[i].p.y);

    n+=;fa[n-]=n-;fa[n-]=n-;

    sort(B,B+NUM);

    for (i=;i<NUM;i++){

        int x=gf(B[i].x),y=gf(B[i].y);

        if (x==y) continue;

        fa[x]=y;

        if (gf(n-)==gf(n-)) return printf("%.6Lf\n",B[i].z),;

    }

}