#include <bits/stdc++.h>   using namespace std;   int n, nn, sum;   vector<double> q;   double x, ans, anss;   int main() {     scanf( %d , &n);     sum = 0;     for (int i = 1; i <= 2 * n; i++) {       scanf( %lf , &x);       ans += (x - floor(x));       if (floor(x) == ceil(x)) sum++;     }     if (sum > n) n = n * 2 - sum;     sum = min(sum, n);     anss = 10000000;     for (int i = n - sum; i <= n; i++) anss = min(anss, fabs(ans - i));     printf( %.3lf , anss);   }   