int a=A2;
int led1=3;
int led2=5;
int led3= 6;

void setup() 
{
pinMode(a, INPUT);
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(led3, OUTPUT);
Serial.begin(9600); 
}

void loop()
{
int value= analogRead(a);
int v=map(value, 0,1023, 0,255);
Serial.println(v);
if (v<=100)
{
digitalWrite(led1, HIGH);
digitalWrite(led3, LOW);
digitalWrite(led2, LOW);
}
else if(v<=200 and v>100)
{
digitalWrite(led2, HIGH);
digitalWrite(led1, LOW);
digitalWrite(led3, LOW);
}
else
{
digitalWrite(led3, HIGH);
digitalWrite(led2, LOW);
digitalWrite(led1, LOW);
}
}