#include <stdio.h> /* fprintf(3), getc(3), stderr, stdin, EOF */
#include <string.h> /* memset(3) */
#include "ascii.h" /* ASCII_HEXADECIMAL_DIGITS_LOWER,
                    * ASCII_HEXADECIMAL_DIGITS_UPPER */
#define SKIPLINE while((c = getc(stdin)) != '\n' && c != EOF)

static char *hex = ASCII_HEXADECIMAL_DIGITS_UPPER
	ASCII_HEXADECIMAL_DIGITS_LOWER;

int main(int argc, char *argv[]){
	int c;
	int i;
	int l; /* line counter */
	char *n;
	long int utf32_lit;
	unsigned char utf8_bytes[8];

	c = '\0';
	i = 0;
	l = 1;
	while(c != EOF){
		memset(utf8_bytes, '0', sizeof utf8_bytes);
		for(
			i = 0, n = NULL, utf32_lit = 0;
			(c = getc(stdin)) != '\n'
			&& c != EOF
			&& i < 10;
			++i
		){
			if(
				(i == 0 && c != 'U')
				|| (i == 1 && c != '+')
				|| i > 10
				|| (i > 1 && (n = strchr(hex, c))
					== NULL)
			){
				fprintf(stderr, "%s: %s: Syntax error.\n",
					argv[0], l);
				SKIPLINE;
				i = -1;
				break;
			}
			if(n != NULL)
				utf32_lit = (utf32_lit << 4) + (n - hex) % 16;
		}
		if(i < 3){
			if(c != '\n' && c != EOF)
				SKIPLINE;
			if(c == EOF)
				return 0;
			continue;
		}
		switch(i =	(utf32_lit < 65536)
			+ (utf32_lit < 2048)
			+ (utf32_lit < 128)){
		case 0: utf8_bytes[0] =
			((utf32_lit >> 18) & 7) + 240; /* 11110xxx */
		case 1:	utf8_bytes[1] = i == 1
			? ((utf32_lit >> 12) & 15) + 224 /* 1110xxxx */
			: ((utf32_lit >> 12) & 63) + 80; /* 10xxxxxx */
		case 2:	utf8_bytes[2] = i == 2
			? ((utf32_lit >> 6) & 31) + 192 /* 110xxxxx */
			: ((utf32_lit >> 6) & 63) + 80; /* 10xxxxxx */
		case 3:	utf8_bytes[3] = i == 3
			? utf8_bytes[3] = utf32_lit & 127 /* 0xxxxxxx */
			: (utf32_lit & 63) + 80; /* 10xxxxxx */
		}
		for( ; i < 4; ++i)
			putc(utf8_bytes[i], stdout);
		++l;
	}
}