#include <stdio.h>

int main(int argc, char** argv)
{
	char* literals;
	int val;

	/* Provide any parameter to percentify most any character */
	if (argc == 1) 
		literals = ",./':1234567890-=_+|!#$^abcdefghijklmnopqrstuvwxyz"
			"ABCDEFGHIJKLMNOPQRSTUVWXYZ\n";
	else
		literals = "/?=\n";
	
	while ((val = fgetc(stdin)), !feof(stdin))
		if (strchr(literals, val))
			fputc(val, stdout);
		else
			fprintf(stdout, "%%%02X", val);

	return 0;
}

