B

#include <cstdio>

unsigned long long my_pow(unsigned long long x, unsigned long long p) {
  unsigned long long tmp = x;
  while (p != 1) {
    tmp *= x;
    p--;
  }
  return tmp;
}

int main(void) {
  unsigned long long n, a, b, n_dig = 0ULL;
  scanf("%llu", &n);

  a = n * 10ULL;
  b = n;
  while (b != 0ULL) {
    b /= 10ULL;
    n_dig++;
  }
  b = n + my_pow(10ULL, n_dig);

  if (a < b) {
    printf("%llu\n", a);
  } else {
    printf("%llu\n", b);
  }
  return 0;
}