#include <stdio.h>
#include <math.h>

#define PI 3.1412759

int main(void) {
  int n, o, i, j;
  int l[10000], u[10000];
  double sx[10000], sy[10000];
  int sdeg[10000];
  
  do {
    scanf("%d %d", &n, &o);
    for(i = 0; i < n; i++)
      scanf("%d", &l[i]);
    double x = 0, y = 0;
    int deg = 0;
    for(j = 0; j < n; j++) {
      deg += u[j];
      x += l[j] * cos( ( (deg + 90) * PI ) / 180 );
      y += l[j] * sin( ( (deg + 90) * PI ) / 180 );
      sx[j] = x;
      sy[j] = y;
      sdeg[j] = deg;
    }
    for(i = 0; i < o; i++) {
      int r;
      scanf("%d", &r);
      scanf("%d", &u[r]);
      deg = sdeg[r - 1];
      x = sx[r - 1];
      y = sy[r - 1];
      u[r] -= 180;
      for(j = r; j < n; j++) {
	deg += u[j];
        x += l[j] * cos( ( (deg + 90) * PI ) / 180 );
        y += l[j] * sin( ( (deg + 90) * PI ) / 180 );
	sx[j] = x;
	sy[j] = y;
	sdeg[j] = deg;
      }
      printf("%4.2f %4.2f\n", x, y);
    }
    printf("\n");
    getchar();
  } while(getchar() == '\n');
  return 0;
}