tarzan - 221

#include <stdio.h>
#include <stdlib.h>

typedef struct {
  int x;
  int y;
} Coordenada;

typedef struct{
  int item;
  int size;
} Node;

Node node[2000];
Coordenada coordenada[2000];

int find (int i) {
  if(node[i].item != i){
    node[i].item = find(node[i].item);
  }
  return node[i].item;
}

void mount(int arvores){
  int i;
  for (i = 0; i < arvores; ++i) {
    scanf("%d %d", &coordenada[i].x, &coordenada[i].y);
    node[i].item = i;
    node[i].size = 1;
  }
}

int compare(int arvores, int alcance){
  int i=0, j=0, final = arvores, find_i, find_j, aux = (alcance * alcance);
  for(i = 0; i < arvores; ++i){
    for (j = 0; j < arvores; ++j) {
      if(((coordenada[i].x - coordenada[j].x) * (coordenada[i].x - coordenada[j].x)) + ((coordenada[i].y-coordenada[j].y) * (coordenada[i].y-coordenada[j].y)) <= aux){
        find_i = find(i);
        find_j = find(j);

        if(find_i != find_j){
         --final ;
         if (node[find_i].size <= node[find_j].size){
           node[find_i].item = find_j;
           node[find_j].size=node[find_j].size+node[find_i].size;
          }
          else {
           node[find_j].item=find_i;
           node[find_i].size=node[find_i].size+node[find_j].size;
          }
        }
      }
    }
  }
  return final ;
}

int main() {
  int arvores, alcance;
  int i, j, aux;

  scanf("%d %d", &arvores, &alcance);
  mount(arvores);
  int final = compare(arvores, alcance);
  if (final != 1)
    printf("N");
  else
    printf("S");

  return 0;
}