#define _GNU_SOURCE
#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#define MAXS 10240

struct seg
{
  unsigned len;
  int deg_angle;
};

static struct seg seg[MAXS];
size_t num_seg;

struct tree
{
  struct tree *left, *right;
  struct seg *seg;
  long double len;
  long double rad_relangle;
};

static struct tree tree[2 * MAXS];
static size_t num_tree;

static void
recompute (struct tree *t)
{
  if (t->seg != NULL)
    t->rad_relangle = (t->seg->deg_angle - 180) * (M_PIl / 180);
  else
    {
      long double x, y;

      x = t->left->len + t->right->len * cosl (t->right->rad_relangle);
      y = t->right->len * sinl (t->right->rad_relangle);
      t->len = hypotl (x, y);
      t->rad_relangle = t->left->rad_relangle + atan2l(y, x);
    }
}

static struct tree *
build_tree (size_t start, size_t num)
{
  struct tree *t;

  t = tree + num_tree++;
  if (num == 1)
    {
      t->left = NULL;
      t->right = NULL;
      t->seg = seg + start;
      t->len = seg[start].len;
    }
  else
    {
      t->left = build_tree (start, num / 2);
      t->right = build_tree (start + num / 2, num - num / 2);
      t->seg = NULL;
    }
  recompute (t);
  return t;
}

static void
update_tree (struct tree *t, size_t num, size_t i)
{
  if (num > 1)
    {
      if (i < num / 2)
	update_tree (t->left, num / 2, i);
      else
	update_tree (t->right, num - num / 2, i - num / 2);
    }
  recompute (t);
}

int
main (void)
{
  unsigned c;
  int first;

  first = 1;
  while (scanf ("%zu%u", &num_seg, &c) == 2)
    {
      size_t i;
      struct tree *root;

      for (i = 0; i < num_seg; i++)
	{
	  scanf ("%u", &seg[i].len);
	  seg[i].deg_angle = 180;
	}
      num_tree = 0;
      root = build_tree (0, num_seg);
      if (first != 0)
	first = 0;
      else
	putchar ('\n');
      while (c != 0)
	{
	  unsigned s, a;

	  c--;
	  scanf ("%u%u", &s, &a);
	  seg[s].deg_angle = a;
	  update_tree (root, num_seg, s);
	  printf ("%.2Lf %.2Lf\n", root->len * cosl (root->rad_relangle + M_PIl / 2),
		  root->len * sinl (root->rad_relangle + M_PIl / 2));
	}
    }
  return EXIT_SUCCESS;
}