I2C to Accel Stepper

#include <AccelStepper.h>
//#include <DMXSerial.h>
#include <Wire.h>

AccelStepper stepper(8, 8, 9, 10, 11);
AccelStepper stepper2(8, 4, 5, 6, 7);

int a = 0;
int b = 0;
int c=0;
int d=0;
int e=0;
const int botao = 13;
//const int botao2 = 13;
int estadoBotao = 0;
int estadoBotao2 = 0;

int mapa = 0;
int mapa2 = 0;
int mapa3 = 0;
int mapa4 = 0;
int mapa5 = 0;

void setup(){

  Wire.begin(8);                // join i2c bus with address #8
  Wire.onReceive(receiveEvent); // register event
  //DMXSerial.init(DMXReceiver);
  stepper.setMaxSpeed(1000);
  stepper.setSpeed(2);
  stepper.setAcceleration (1000);

  stepper2.setMaxSpeed(500);
  stepper2.setSpeed(0);
  stepper2.setAcceleration (500);

  pinMode(botao,INPUT);
  //pinMode(botao2,INPUT);

                                   while (estadoBotao == LOW) {
                                          estadoBotao = digitalRead(botao);
                                          stepper.move(4);
                                          stepper.run();}

                                         delay(500);

                                      stepper.setCurrentPosition(0);

                                      for (int i = 0; i < 15; i++){
                                      delay(50);
                                      stepper.move(-1);
                                      stepper.run();
                                      }
                                      delay(500);
                                      stepper.setCurrentPosition(0);


                                      for (int i = 0; i < 220; i++){
                                      delay(100);
                                      stepper2.move(-1);
                                      stepper2.run();
                                      }
                                     delay(500);
                                     stepper2.setCurrentPosition(0);
                                      for (int i = 0; i < 5; i++){
                                      delay(50);
                                      stepper2.move(1);
                                      stepper2.run();
                                      }
                                      delay(500);
                                      stepper2.setCurrentPosition(0);
                                      //stepper2.setMaxSpeed(600);

}

void loop(){

//unsigned long lastPacket = DMXSerial.noDataSince();

  //if (lastPacket < 5000) {
        //a = ( DMXSerial.read(1));
             mapa=map(a,0,255,0,-2400);
       //b = ( DMXSerial.read(2));
            mapa2=map(b,0,255,0,200);
       //e = ( DMXSerial.read(6));  //Velocidade motores
            mapa3=map(e,0,255,1000,50);
            mapa4=map(e,0,255,1000,2);
            //}

stepper.setMaxSpeed(mapa3);
stepper2.setMaxSpeed(mapa3);

stepper2.moveTo(d);
stepper2.run();

stepper.moveTo(c);
stepper.run();

            if(c<mapa){
              c = c+1;
            }
            if(c>mapa){
             c = c-1;
             }

             if(d<mapa2){
              d = d+1;
            }
            if(d>mapa2){
             d = d-1;
             }

}
void receiveEvent(int howMany) {
  a = Wire.read();
  b = Wire.read();
  e = Wire.read();
}