#include <stdio.h>

#define MEM_SIZE 16

#define CONSTRAIN(x) (x) % 16

typedef void (*instruction)(void);

int memory[MEM_SIZE];

int pc;
int is;
int r0;
int r1;

void add () {
   pc = CONSTRAIN (pc + 1);
   r0 = CONSTRAIN (r0 + r1);
}

void sub () {
   pc = CONSTRAIN (pc + 1);
   r0 = CONSTRAIN (r0 - r1);
}

void incR0 () {
   pc = CONSTRAIN (pc + 1);
   r0 = CONSTRAIN (r0 + 1);
}

void incR1 () {
   pc = CONSTRAIN (pc + 1);
   r1 = CONSTRAIN (r1 + 1);
}

void decR0 () {
   pc = CONSTRAIN (pc + 1);
   r0 = CONSTRAIN (r0 - 1);
}

void decR1 () {
   pc = CONSTRAIN (pc + 1);
   r1 = CONSTRAIN (r1 + 1);
}

void ding () {
   pc = CONSTRAIN (pc + 1);
   printf("DING!\n");
}

void out () {
   printf("%d\n", CONSTRAIN (memory[pc + 1]));
   pc = CONSTRAIN (pc + 2);
}

void loadR0 () {
   r0 = memory[memory[CONSTRAIN (pc + 1)]];
   pc = CONSTRAIN (pc + 2);
}

void loadR1 () {
   r1 = memory[memory[CONSTRAIN (pc + 1)]];
   pc = CONSTRAIN (pc + 2);
}

void storeR0 () {
   memory[memory[CONSTRAIN (pc + 1)]] = r0;
   pc = CONSTRAIN (pc + 2);
}

void storeR1 () {
   memory[memory[CONSTRAIN (pc + 1)]] = r1;
   pc = CONSTRAIN (pc + 2);
}

void jmp () {
   pc = memory[CONSTRAIN (pc + 1)];
}

void jmpR0 () {
   if (r0 == 0) {
      jmp();
   } else {
      pc = CONSTRAIN (pc + 1);
   }
}

void jmpNotR0 () {
   if (r0 != 0) {
      jmp();
   } else {
      pc = CONSTRAIN (pc + 1);
   }
}

instruction instructions[16] = {add, sub, incR0, incR1, decR0, decR1, ding, out, loadR0, loadR1, storeR0, storeR1, jmp, jmpR0, jmpNotR0};

int main (int argc, char ** argv) {

   int i;
    for (i=0;i<argc - 1;i++) {
      memory[i] = CONSTRAIN(atoi(argv[i + 1]));
   }
   for (;i<=MEM_SIZE;i++) {
      memory[i] = 0;
   }

   pc = is = r0 = r1 = 0;

   while (1) {
      is = memory[pc];
      if (is == 0) {
         break;
      }
      instructions[is - 1]();
   }

    return 0;
}