#include <bits/stdc++.h>
using namespace std;
struct cell {
int l, r;
double b;
};
const int MAX_N = 2e5;
int a[MAX_N + 1];
long long s[MAX_N + 1];
vector<cell> path;
double bary( int l, int r ) {
return (double)(s[r] - s[l - 1]) / (r - l + 1);
}
int main() {
int n;
cin >> n;
for ( int i = 1; i <= n; i++ ) {
cin >> a[i];
s[i] = s[i - 1] + a[i];
}
int l = 1, r = n;
while ( l != r ) {
if ( bary( l, r - 1 ) >= bary( 1, n ) )
r--;
else
l++;
path.push_back( { l, r, bary( l, r ) } );
}
sort( path.begin(), path.end(), []( cell a, cell b ) {
return a.b > b.b;
} );
double minDif = 1e9;
double minB = bary( 1, n );
for ( cell c: path ) {
minDif = min( minDif, c.b - minB );
minB = min( minB, bary( c.l - 1, c.r - 1 ) );
}
minDif = min( minDif, bary( 1, n ) - minB );
cout << setprecision( 7 ) << fixed << minDif;
return 0;
}
