#include<stdio.h>
#include<stdint.h>

int main(){
	uint8_t high = 0xff;
	uint8_t key = 2;

	uint8_t enc = high + key;
	printf("enc = %d\n", enc);

	uint8_t dec = enc - key;
	printf("dec = %d\n", dec);

	return 0;
}