pat-bl-1063

/**
* pat-bl-1063
* 2017-01-24
* C version
* Author: fengLian_s
*/
#include<stdio.h>
#include<math.h>
int main()
{
freopen("in.txt", "r", stdin);
int n;
scanf("%d", &n);
double mod, maxMod = 0;
for(int i = 0;i < n;i++)
{
double a, b;
scanf("%lf %lf", &a, &b);
//printf("%lf %lf\n", a, b);
mod = sqrt(a * a + b * b);
if(maxMod < mod)
maxMod = mod;
}
printf("%.2lf\n", maxMod);
}