#include <cmath>#include <cstdio>using namespace std;const long double PI = M_PI;const long double EPS = 1e-8;const int MAXN = 128;int main() {bool blank = false;int n;long double s, a, ca, sa;long double x[MAXN], y[MAXN];while (scanf("%d", &n) != EOF && n > 0) {if (blank) {puts("");} else {blank = true;}s = 0;for (int i = 0; i < n; ++i) {scanf("%Lf%Lf", &x[i], &y[i]);if (i > 0) {s = fmod(s + atan2(y[i] - y[i - 1], x[i] - x[i - 1]), 2 * PI);}}while (s < 0) {s += 2 * PI;}a = s < EPS ? 0 : (2 * PI - s) / (n - 1);printf("%.16Lfn%.16Lfn", 0.0L, a);ca = cos(a);sa = sin(a);for (int i = 0; i < n; ++i) {printf("%.16Lf %.16Lfn", ca * x[i] - sa * y[i], sa * x[i] + ca * y[i]);}}return 0;}
