#include<stdio.h>
#include<math.h>

int main()
{
    int N, a, b, i;
    double max = 0.0, Max;
    scanf("%d", &N);

    for(i=0; i<N; i++)
    {
        scanf("%d %d", &a, &b);
        if(max < a*a+b*b)
        {
            max = a*a+b*b;
        }
    }
    max = pow(max, 0.5);
    Max = (int)(max*100 + 0.5) * 0.01;
    printf("%.2lf", Max);
}