#include#includeusingnamespacestd;
int main()
{
int N;
scanf("%d",&N);
float a, b;
float max=0.0;
for (int i = 0; i < N; i++)
{
scanf("%f%f", &a, &b);
float c = a*a + b*b;
if (max < sqrt(c))
max = sqrt(c);
}
printf("%.2f", max);
return0;
}//学会使用c的输入输出是一样很重要的事