const int LED=22;
const int button=21;

int lastState_button = LOW;
int State_LED = LOW;
 
 void setup()
 {
   pinMode(LED,OUTPUT);
   pinMode (button,INPUT);

 }
 void loop()
 {
   int buttonState = digitalRead(button);
   if (buttonState != lastState_button){
     lastState_button = buttonState;
   if (lastState_button == LOW){
     if (State_LED == HIGH){
       State_LED = LOW;
     }else{
       State_LED = HIGH;
     }
   }
   digitalWrite(LED,State_LED);
   }
 }