#include #include #include int b[20000][2], n, n2, i, x, y, key[2], *found; double dx, dy; int compare(const void *p1, const void *p2){ if(*((int *)p1) == *((int *)p2)) return(*((int *)p1 + 1) - *((int *)p2 + 1)); return(*((int *)p1) - *((int *)p2)); } int main(){ while(1){ scanf("%d\n", &n); if(n == 0) break; for(x = y = i = 0; i < n; i++){ scanf("%d %d\n", &b[i][0], &b[i][1]); x += b[i][0]; y += b[i][1]; } dx = (double)x / n; dy = (double)y / n; qsort(b, n, 2 * sizeof(int), compare); n2 = n + 1 / 2; for(i = 0; i < n2; i++){ key[0] = (dx - b[i][0]) * 2 + b[i][0]; key[1] = (dy - b[i][1]) * 2 + b[i][1]; if(bsearch(&key, b, n, 2 * sizeof(int), compare) == NULL){ printf("This is a dangerous situation!\n"); break; } } if(i == n2){ dx = floor(dx + .5); dy = floor(dy + .5); printf("V.I.P. should stay at (%.1lf,%.1lf).\n", dx, dy); } } return(0); }