#include    <stdio.h>
 
#define     __DEBUG__
#undef      __DEBUG__
 
#define     WORDWIDTH       4
#define     ADDRWIDTH       8
#define     MEMSIZE         256
 
typedef enum {
    LD ,           /* LD x    A = memory[x]                   */
    ST ,           /* ST x    memory[x] = A                   */
    SWP ,           /* SWP     swap(A, B)                      */
    ADD ,           /* ADD     A = low(A + B), B = high(A + B) */
    INC ,           /* INC     A = A + 1                       */
    DEC ,           /* DEC     A = A - 1                       */
    BZ ,           /* BZ x    if(A == 0) pc = x               */
    BR ,           /* BR x    pc = x                          */
    STP             /* STP     stop the program                */
}   Instruction;
 
unsigned int    accuA;
unsigned int    accuB;
unsigned int    pc;
unsigned int    memory[MEMSIZE];
FILE            * inputFile;
FILE            * outputFile;
 
int     ReadMemory (void);
void    Execute     (void);
void    PrintMemory (void);
int     InitInput   (void);
void    Cleanup     (void);
 
int main(void) {
    if(InitInput())
        return 1;
 
    while(1) {
        if(!ReadMemory())
            break;
 
        Execute();
        PrintMemory();
    }
 
    Cleanup();
 
    return 0;
}
 
int ReadMemory(void) {
    char    ch;
    int     i;
 
    ch = fgetc(inputFile);
    while((ch < '0' || ch > '9') && (ch < 'A' || ch > 'F'))
        ch = fgetc(inputFile);
 
    if(ch == '8')
        return 0;
 
    for(i = 1; i < MEMSIZE; ) {
        ch = fgetc(inputFile);
 
        if(ch >= '0' && ch <= '9')
            memory[i++] = ch - '0';
        else
            if(ch >= 'A' && ch <= 'F')
                memory[i++] = ch - 'A' + 10;
    }
 
    return 1;
}
 
void Execute(void) {
    unsigned    int instr;
    unsigned    int low;
    unsigned    int high;
    unsigned    int opr;
    unsigned    int sum;
                int finished = 0;
 
    accuA   =   0;
    accuB   =   0;
    pc      =   0;
 
    while(!finished) {
       instr = memory[pc++];
 
        switch(instr) {
            case LD :
                    high    =   memory[pc++];
                    low     =   memory[pc++];
                    opr     =   (high << WORDWIDTH) + low;
                    accuA   =   memory[opr];
                    break;
 
            case ST :
                    high        =   memory[pc++];
                    low         =   memory[pc++];
                    opr         =   (high << WORDWIDTH) + low;
                    memory[opr] =   accuA;
                    break;
 
            case SWP:
                    accuA ^= accuB ^= accuA ^= accuB;
                    break;
 
            case ADD:
                    sum     =   (accuA + accuB) % 0x100;
                    accuA   =   sum & 0x0f;
                    accuB   =   (sum & 0xf0) >> WORDWIDTH;
                    break;
 
            case INC:
                    if(++accuA == 0x10)
                        accuA = 0x0;
                    break;
 
            case DEC:
                    if(accuA == 0x0)
                        accuA = 0xf;
                    else
                        accuA--;
                    break;
 
            case BZ :
                    high    =   memory[pc++];
                    low     =   memory[pc++];
                    opr     =   (high << WORDWIDTH) + low;
                    if(accuA == 0x0)
                        pc = opr;
                    break;
 
            case BR :
                    pc = memory[pc + 1];
                    break;
 
            case STP:
                    finished = 1;
                    break;
        }
    }
}
 
void PrintMemory(void) {
    int i;
 
    for(i = 0; i < MEMSIZE; i++)
        if(memory[i] < 10)
            fprintf(outputFile, "%d", memory[i]);
        else
            fprintf(outputFile, "%c", memory[i] - 10 + 'A');
 
    fprintf(outputFile, "\n");
    fflush(outputFile);
}
 
 
int InitInput(void) {
#ifdef __DEBUG__
 
    inputFile   =   fopen("input.txt" , "r");
    outputFile =   fopen("output.txt", "w");
 
    if(inputFile == NULL) {
        printf("Cannot open input file.\n");
        return 1;
    }
 
    if(outputFile == NULL) {
        printf("Cannot open output file.\n");
        return 1;
    }
 
#else
 
    inputFile   =   stdin;
    outputFile =   stdout;
 
#endif
 
    return 0;
}
 
void Cleanup(void) {
#ifdef __DEBUG__
 
    fclose(inputFile);
    fclose(outputFile);
 
#endif
}