int measurePaper() {

  ///write code here to measure length of paper

  Stop(0);

  delay(1000);

  //first, line each wheel up with the edge of the paper

  leftMotorSpeed=0;

  rightMotorSpeed=-100;

  Forward(0);

  while(digitalRead(PaperSensor)==LOW && !lost);

  if (lost) return;

  Stop(0);

  delay(1000);

  leftMotorSpeed=-100;

  rightMotorSpeed=0;

  Forward(0);

  int psmvg[4];

  int total1=0;

  for (byte i =0;i<4;i++) total1+=psmvg[i]=analogRead(PaperSensor2);

  int index1=0;

  while(total1/4>=30 && !lost) {

    total1-=psmvg[index1];

    total1+=psmvg[index1]=analogRead(PaperSensor2);

    index1=(index1+1)%4;

  }

  if (lost) return 0;

  leftTick=0;

  while(leftTick<2);

  Stop(0);

  delay(1000);

 //drive forward

  leftMotorSpeed=leftMotorDefaultSpeed*0.7;

  rightMotorSpeed=rightMotorDefaultSpeed*0.8;

  Forward(0);

  int lastread;

  while ((lastread=digitalRead(PaperSensor))==HIGH);

  long atleast=millis(); // set time

  while(millis()-atleast<5) {

    int currentread=digitalRead(PaperSensor);

    if (lastread!=currentread) { atleast=millis(); }

    lastread=currentread;

  }

  //setting up sensors after we hit the inital edge of the paper

  leftTick=0;

  bool lastps1 = digitalRead(PaperSensor);

  int lastps2;

  int total=0;

  int index=0;

  for (int i=0; i<4;i++) total+=paperSensorMovingAverage[i]=analogRead(PaperSensor2);

  long lastChange=millis();

  //drive until edge of paper

  while (1 && !lost) {

    bool ps1 = digitalRead(PaperSensor);

    total-=paperSensorMovingAverage[index];

    paperSensorMovingAverage[index]=analogRead(PaperSensor2);

    index=(index+1)%4;

    int ps2=total/4;

    if (ps1!=lastps1) lastChange=millis();

    if (ps2<30 && millis()-lastChange>50 && ps1) break; //we have crossed over the paper

    lastps1=ps1;

  }

  if (lost) return 0;

  Stop(0);

  //calculate length and return/display on screen

  paperLength=(int)(leftTick*(0.945)); 

  currentMenu=paperLengthMenu;

  drawCurrentMenu();

  delay(1000);

  return paperLength;

}