1063 计算谱半径
#include <iostream>
#include<cmath>
#include<iomanip>
using namespace std;
int main()
{
int n;
cin>>n;
int a[n],b[n];
double pu=0;
for(int i=0;i<n;i++)
{
cin>>a[i]>>b[i];
if(a[i]*a[i]+b[i]*b[i]>pu*pu)
{
pu=sqrt(a[i]*a[i]+b[i]*b[i]);
}
}
cout<<fixed<<setprecision(2)<<pu;
return 0;
}