int c=0,nc=0,ec=0,n=0,e=0,w=0,s=0;
int Redn=13,yellown=12,greenn=32,Reds=15,yellows=2,greens=4,Rede=23,yellowe=22,greene=21,Redw=33,yelloww=25,greenw=26;
int pinn=18,pinw=27,pine=5,pins=14;
void north()
{
    if(nc==0)
    {
      digitalWrite(Reds,0);
      digitalWrite(Redn,0);
      digitalWrite(greene,0);
      digitalWrite(greenw,0);
      digitalWrite(yellowe,1);
      digitalWrite(yellown,1);
      digitalWrite(yellows,1);
      digitalWrite(yelloww,1);
      delay(500);
      digitalWrite(yellowe,0);
      digitalWrite(yellown,0);
      digitalWrite(yellows,0);
      digitalWrite(yelloww,0);
      digitalWrite(Rede,1);
      digitalWrite(Redw,1);
      digitalWrite(greenn,1);
      digitalWrite(greens,1);
      delay(4000);
    }
    nc=1;
    ec=0;
}
void east()
{
    if(ec==0)
    {
      digitalWrite(Rede,0);
      digitalWrite(Redw,0);
      digitalWrite(greens,0);
      digitalWrite(greenn,0);
      digitalWrite(yellowe,1);
      digitalWrite(yellown,1);
      digitalWrite(yellows,1);
      digitalWrite(yelloww,1);
      delay(500);
      digitalWrite(yellowe,0);
      digitalWrite(yellown,0);
      digitalWrite(yellows,0);
      digitalWrite(yelloww,0);
      digitalWrite(Redn,1);
      digitalWrite(Reds,1);
      digitalWrite(greene,1);
      digitalWrite(greenw,1);
      delay(4000);
    }
    nc=0;
    ec=1;
}
void saver()
{
    nc=0;
    ec=0;
}

void setup()
{
  pinMode(Redn,OUTPUT);
  pinMode(yellown,OUTPUT);
  pinMode(greenn,OUTPUT);
  pinMode(Rede,OUTPUT);
  pinMode(yellowe,OUTPUT);
  pinMode(greene,OUTPUT);
  pinMode(Redw,OUTPUT);
  pinMode(yelloww,OUTPUT);
  pinMode(greenw,OUTPUT);
  pinMode(Reds,OUTPUT);
  pinMode(yellows,OUTPUT);
  pinMode(greens,OUTPUT);
  pinMode(pinn,INPUT);
  pinMode(pine,INPUT);
  pinMode(pins,INPUT);
  pinMode(pinw,INPUT);
}
void loop()
{
    
    n=digitalRead(pinn);
    s=digitalRead(pins);
    e=digitalRead(pine);
    w=digitalRead(pinw);
    if(n==0 and s==0 and e==0 and w==0)
        saver();
    else if(n==0 and s==0 and (w==1 or e==1))
        east();
    else if(w==0 and e==0 and (n==1 or s==1))
        north();
    else if((n+e)==2 or (n+w)==2 or (s+w)==2 or (s+e)==2)
        if(c==0)
        {
            north();
            c=1;
        }
        else
        {
            east();
            c=0;
        }
}