# include <stdio.h>
# include <stdlib.h>

int main(void) {
    double n;
	double x;
	printf("Veuillez entrer un réel : ");
	scanf("%lf", &n);
	getchar();
	printf("Veuillez entrer un réel : ");
	scanf("%lf", &x);
	getchar();
	/* TO DO */
		printf("\n %d \n", n);
		}
	else if((n%3) == 1){
		printf("\n %d \n", n-1);
		}
	else {
		printf("\n %d \n", n+1);
	}
 
  return EXIT_SUCCESS; 
}