#include <iostream>
#include <cstdio>
#include <math.h>
using namespace std;
int main()
{
int n;
scanf("%d",&n);
double maxn=0;
for(int i=0;i<n;i++){
double a,b;
scanf("%lf %lf",&a,&b);
double temp=sqrt(a*a+b*b);
if(temp>maxn) maxn=temp;
}
printf("%0.2f",maxn);
return 0;
}
#include <cstdio>
#include <math.h>
using namespace std;
int main()
{
int n;
scanf("%d",&n);
double maxn=0;
for(int i=0;i<n;i++){
double a,b;
scanf("%lf %lf",&a,&b);
double temp=sqrt(a*a+b*b);
if(temp>maxn) maxn=temp;
}
printf("%0.2f",maxn);
return 0;
}