int p = 0;
void setup() {
  // put your setup code here, to run once:
pinMode(3, OUTPUT);
pinMode(7, INPUT_PULLUP);
}

void loop() {
  // put your main code here, to run repeatedly:
int state = 0;
state = digitalRead(7);
if(state == LOW && p ==0){
digitalWrite(3, HIGH);
delay(10);
p = 1;
}
else if( state == LOW && p == 1){
digitalWrite(3, LOW);
delay(10);
p = 0;
}
else{

}
}