1063

#include<iostream> 
#include<stdio.h>
#include<string.h>
#include<cmath>
#include<algorithm>
using namespace std;
#define N 100
int main()
{
    int n;
    scanf("%d",&n);
    double ans=0;
    for(int i=1;i<=n;i++)
    {
        int a,b;
        scanf("%d%d",&a,&b);
        ans=max(ans,sqrt(a*a+b*b));
    }
    printf("%0.2lf\n",ans);
    return 0;
}