2.cpp

#include <cstdio>

using namespace std;

int main() {
  setbuf(stdout, NULL);

  int nCase;
  scanf("%d", &nCase);

  for (int iCase = 0; iCase < nCase; ++iCase) {
    long long a, b, c;

    printf("Case #%d\n", iCase + 1);
    scanf("%lld %lld %lld", &a, &b, &c);

    while (c-- > 0) {
      long long n, k;
      scanf("%lld %lld", &n, &k);
      long long t = a * k + b;
      long long u = b * k + a;
      long long x = n / t;
      long long y = n % t;

      if (y <= a && x * (t - u) < y) {
        printf("b");
      } else {
        printf("a");
      }
    }
    printf("\n");
  }

  return 0;
}