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

char rune[8];

#define get(c) ((c = fgetc(stdin)) != EOF)
#define utf8_multibyte(c) (c & 0x80)
#define utf8_continued(c) ((c & 0xC0) == 0x80)

int main(void)
{
	int c;
	unsigned i;
	while (get(c)) {
		i = 0;
		rune[i++] = c;
		if (utf8_multibyte(c)) {
			while (get(c) && utf8_continued(c)) {
				rune[i++] = c;
				assert(i < sizeof(rune));
			}
			ungetc(c, stdin);
		}
		rune[i] = '\0';
		printf("rune: %s\n", rune);
	}
	return 0;
}