#include <stdio.h>#include <stdlib.h>#include <string.h>#include <iostream>#include <algorithm>#include <queue>#include <stack>#include <math.h>using namespace std;const int MAX = 1010;struct point{ double x,y;};point p[MAX];int main(){int n;while( ~scanf("%d",&n) ){for(int i=0; i<n; i++)scanf("%lf %lf",&p[i].x,&p[i].y);printf("%d",n);for(int i=0; i<n; i++)printf(" %.6lf %.6lf",(p[i].x + p[(i+1)%n].x)/2.0,(p[i].y + p[(i+1)%n].y)/2.0);printf("n");}return 0;}
