#include<cstdio>
#include<iostream>
#include<map>
using namespace std;

struct point {
  int x, y;
  bool operator=(const point & rhs) const{
    if(x == rhs.x && y == rhs.y)
      return true;
    return false;
  }
  bool operator<(const point & rhs) const {
    if(x == rhs.x)
      return y < rhs.y;
    return x < rhs.x;
  }
};


int main() {
  int i,j,k,n,m;
  point po;
  bool flag;
  while(scanf("%d %d",&po.x, &po.y) == 2) {
    map<point, int> mp;
    map<int, int> mp2; 
    if(po.x > po.y)
      swap(po.x, po.y);
    mp[po]++;
    mp2[po.x]++;
    mp2[po.y]++; 
    for(i=0;i<5;++i) {
      scanf("%d %d", &po.x, &po.y);
      if(po.x > po.y)
        swap(po.x, po.y);
      mp2[po.x]++;
      mp2[po.y]++; 
      mp[po]++; 
    }
    flag = true;
    for(auto pi = mp.begin(); pi != mp.end(); ++pi) {
      //printf("%d %d %d\n", pi->first.x, pi->first.y, pi->second);
      if(pi->second % 2 != 0) {
        flag = false;
        break;
      }
    }
    for(auto pi = mp2.begin(); pi != mp2.end(); ++pi) {
      //printf("[%d %d] ", pi->first, pi->second);
      if(pi->second % 4 != 0) {
        flag = false;
        break;
      }
    }
    if(flag)
      puts("POSSIBLE");
    else
      puts("IMPOSSIBLE");
  }
  return 0;
}