/*------------------------------------------------------------------------------
 * problem017.c: Primary Arithmetic (5.9.1)
**----------------------------------------------------------------------------*/

/* Copyright (c) 2009 Peter Bui. All Rights Reserved.
 *
 * Peter Bui <pbui@cse.nd.edu>
 *
**------------------------------------------------------------------------------
 * Includes
**----------------------------------------------------------------------------*/

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

/*------------------------------------------------------------------------------
 * Constants 
**----------------------------------------------------------------------------*/

#define NMAX_DIGITS 11

#define c2i(c)	(int)((c) - '0')

/*------------------------------------------------------------------------------
 * Functions
**----------------------------------------------------------------------------*/

int
count_carries(char a[], char b[])
{
    char *ap, *bp;
    int   ia, ib, s, c;

    ap = &a[strlen(a) - 1];
    bp = &b[strlen(b) - 1];
    s  = 0;
    c  = 0;

    while (ap >= a || bp >= b) {
	ia = (ap >= a) ? c2i(*ap--) : 0;
	ib = (bp >= b) ? c2i(*bp--) : 0;

	s += ia + ib;
	if (s > 9) {
	    s -= 9;
	    c++;
	} else {
	    s = 0;
	}
    }

    return (c);
}

/*------------------------------------------------------------------------------
 * Main Execution
**----------------------------------------------------------------------------*/

int
main(int argc, char* argv[]) 
{
    char a[NMAX_DIGITS];
    char b[NMAX_DIGITS];
    int  c;

    while (scanf("%s %s", a, b) != EOF) {
	if (strcmp(a, "0") == 0 && strcmp(b, "0") == 0)
	    break;

	c = count_carries(a, b);
	switch (c) {
	    case 0:  printf("No carry operation.\n");     break;
	    case 1:  printf("1 carry operation.\n");      break;
	    default: printf("%d carry operations.\n", c); break;
	}
    }

    return (EXIT_SUCCESS);
}

/*------------------------------------------------------------------------------
 * vim: sts=4 sw=4 ts=8 ft=cpp
**----------------------------------------------------------------------------*/