#include<stdio.h>
#include<assert.h>

main()
{
	FILE *fp;
	fp=fopen("yesdata", "r");
	assert(fp);
	printf("yesdata exist\n");
	fclose(fp);

	fp=fopen("nodata","r");
	assert(fp);
	
	printf("nodata exist\n");
	fclose(fp);
	exit(0);
}