t = input()
while not t.strip():
  t = input()
t = int(t)
for _ in range(t):
  line = input()
  while not line.strip():
    line = input()
  n, k = map(int, line.split())
  s = input()
  while not s.strip():
    s = input()
  n = len(s)
  k = min(n, k + 1)
  same, extra = n // k, n % k
  ans = int(s)
  for mask in range(0, 1 << k):
    if bin(mask).count('1') != extra:
      continue
    at, total = 0, 0
    for i in range(0, k):
      l = same + (mask >> i & 1)
      total += int(s[at : min(n, at + l)])
      at += l
      if at >= n: break
    ans = min(ans, total)
  print(ans)