#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <map>
#include <stack>
#include <deque>
#include <set>
#include <string>
#include <limits>
#include <fstream>

using namespace std;

int main(){
        freopen("input.txt", "rt", stdin);
        freopen("output.txt", "wt", stdout);
        int n;
        cin >> n;
        vector < vector <double> > a(n, vector <double> (n, 0));
        for (int i = 0; i < n; i++){
                for (int j = 0; j < n; j++){
                        scanf("%lf", &a[i][j]);
                }
        }
        double det = 1;
        for (int i = 0; i < n; i++){
                int row = i;
                int mx = a[i][i];
                for(int k = i+1; k < n; k++){
                        if (abs(a[k][i]) > mx){
                                row = k;
                                mx = abs(a[k][i]);
                        }
                }
                if (row != i) {
                        det *= -1;
                        swap(a[row], a[i]);
                }
                for (int j = i+1; j < n; j++){
                        double e = a[j][i]/a[i][i];
                        for (int k = i; k < n; k++){
                                a[j][k] -= e*a[i][k];
                        }
                }
        }
        for (int i = 0; i < n; i++)
                det *= a[i][i];
        printf("%.15lf", det);
        return 0;
}