public int nextState() {
		if(mental_state == 0) {
			mental_state = 1;
		} else if(mental_state == 1) {
			mental_state = 2;
		} else if(mental_state == 2) {
			mental_state = 3;
		} else if(mental_state == 3) {
			mental_state = 4;
		} else if (mental_state == 4) {
			mental_state = 0;
		}
		return mental_state;
	}