#include <stdio.h>

#define INPUT_FILE	"factorial.in"
#define OUTPUT_FILE	"factorial.out"

int main()
{
	unsigned long p;
	unsigned int n;
	FILE *f;

	/* read p */
	f = fopen(INPUT_FILE, "rt");
	fscanf(f, "%ld", &p);
	fclose(f);

	/* calculate n */
	n = -1;

	/* write n */
	f = fopen(OUTPUT_FILE, "wt");
	fprintf(f, "%d", n);
	fclose(f);

	return 0;
}