#include <bits/stdc++.h>
#define int long long
#define _1 first
#define _2 second
#define yes cout<<"Yes\n"
#define nah cout<<"No\n"
#define FFF ios_base::sync_with_stdio(0);cin.tie(0);
#define ipr pair<int,int>
#define ret return
#define intt int32_t
#define mid ((l+r)/2)
#define pb push_back
#define ll long long
#define ld long double
#define lll __int128_t
using namespace std;
int tst, ts;
const intt mo = 1e9 + 7, dx[] = {-1, 1, 0, 0}, dy[] = {0, 0, -1, 1};
int mul( int x, int y ) {
ret ( ( x % mo ) * ( y % mo ) ) % mo;
ret x*y;
}
int pwo( int x, int y ) {
int res = 1;
for( int i = 63; i + 1; i-- )
res = mul( res, res * ( ( 1ll << i )&y ? x : 1 ) );
ret res;
}
int dvii( int x, int y ) {
ret mul( x, pwo( y, mo - 2 ) );
}
int oo( char x ) {
ret ( int )x - '0';
}
int lgg( int x, int y ) {
int u = 0;
while( x ) {
u++;
x /= y;
}
ret u;
}
int mun( int x, int y ) {
while( x < y )x += mo;
ret ( x - y ) % mo;
}
int add( int x, int y ) {
ret x + y - ( mo * ( x + y >= mo ) );
ret x + y;
}
int lcm( int x, int y ) {
ret ( x * y ) / __gcd( x, y );
}
#define endl '\n'
const int M = 2007, N = 2e5 + 7, N2 = 5e3 + 7, inf = 3e9+7;
int n,L;
ipr a[N];
pair<ld,ld>b[N];
ld get(ld x,ld y){
ld p=(x*x)-(y*y);
p=(ld)sqrt(p);
ret p;
}
int is(ld x){
int k=0;
for(int i=0;i<n;i++)
if(a[i]._1+get(x,a[i]._2)>=0)b[k]={a[i]._1-get(x,a[i]._2),a[i]._1+get(x,a[i]._2)},k++;
sort(b,b+k);
ld o=0;
int i=0;
while(i<k&&b[i]._1<=o)
o=max(o,b[i]._2),i++;
ret (o>=L);
}
void solve() {
cin>>n>>L;
for(int i=0;i<n;i++)
cin>>a[i]._1>>a[i]._2;
for(int i=0;i<n;i++)
a[i]._2=abs(a[i]._2);
ld l=0.0,r=inf+0.1;
while(r-l>0.000001){
if(is(mid))
r=mid;
else
l=mid;
}
cout<<fixed<<setprecision(6)<<(ld)r<<endl;
}
intt main() {
FFF/*
freopen("convention2.in", "r", stdin);
freopen("convention2.out", "w", stdout);/*
for( int i = 2; i < N; i++ ) {
if( sv[i] == 0 ) {
for( int j = i + i; j < N; j += i )
sv[j] = 1;
}
}
ff[0] = 1;
for( int i = 1; i < N; i++ )
ff[i] = mul( ff[i - 1], i );
*/
tst = 1;
//cin >> tst;
for( ts = 1; ts <= tst; ts++ ) {
solve();
}
}
