bluescreen

#include <cstdio>
#include <cmath>

using namespace std;

const int MAX_N = 4005;
double a[MAX_N];
int low[MAX_N], high[MAX_N];
double sol[2005][2005];

int main(){

    freopen("bluescreen.in","r",stdin);
    freopen("bluescreen.out","w",stdout);

    int N;
    double sum_initial = 0;
    scanf("%d\n",&N);

    for(int i = 1;i <= N*2; ++i){

        scanf("%lf ",&a[i]);
        low[i] = floor(a[i]);
        high[i] = ceil(a[i]);
        sum_initial += a[i];
    }

    sol[0][0] = sum_initial;
    for(int i = 1; i <= N;++i){

        sol[0][i] = sol[0][i-1] + high[i] - a[i];
        sol[i][0] = sol[i-1][0] + low[i] - a[i];
    }
    for(int i = 1; i <= N; ++i)
        for(int j = 1; j <= N; ++j){

            double aux_low = sol[i-1][j] + low[i+j] - a[i+j];
            double aux_high = sol[i][j-1] + high[i+j] - a[i+j];
            if(fabs(sum_initial - aux_low) < fabs(sum_initial - aux_high))
                sol[i][j] = aux_low;
            else sol[i][j] = aux_high;
        }

    printf("%.3lf",fabs(sum_initial - sol[N][N]));

    fclose(stdin);
    fclose(stdout);
return 0;
}