from itertools import permutations
import sys
import gmpy2
sys.set_int_max_str_digits(200002)
T = int(input())
for _ in range(T):
    n, k = map(int, input().split())
    s = input()
    ans = int(s)
    k = min(k, n-1)+1
    u = n//k
    r = n % k
    grp = [u]*(k-r)+[u+1]*r
    for lst in permutations(grp):
        i = 0
        cur = 0
        for x in lst:
            cur += int(s[i:i+x])
            i+=x
        ans = min(ans, cur)
    print(ans)