#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;
int main() {
int n;
cin >> n;
double max = 0;
for(int i = 0;i<n;i++){
double a;
cin>>a;
if(a<0)a=fabs(a);
if(a>max)max=a;
}
cout<<fixed<<setprecision(2)<<max;
}
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