# [n,k]=map(int(),input().split(' '))
# print(n,k)
global cnt
global n,k
cnt = 0
N = 200010
dp = [[-1 for j in range(6+3)] for i in range(N)]
sum = [0 for i in range(N)]
dd = [0 for i in range(N)]
lens = [[-1 for j in range(8)] for i in range(800)]
tmp = [-1 for i in range(8)]
def get(l,r,num):
    res = 0
    for i in range(l,r+1):
        res*=10
        res+=int(num[i])
    return res

def dfs(len,bk,d,mx):
    global n, k
    global cnt
    if d>=mx:
        if(len!=n):
            return
        cnt = cnt + 1
        for i in range(mx):
            lens[cnt][i] = tmp[i]
    else :
        for i in range(-1,2):
            tmp[d] = bk+i
            dfs(len+bk+i,bk,d+1,mx)



def main():
    global n,k,cnt
    cnt=0
    n,k = map(int,input().split())
    num = input()
    ans = int(num)
    num='.'+num
    bk = n//(k+1)
    dfs(0,bk,0,k+1)
    dd[n]=1
    dd[n+1]=1
    for i in range(n,0,-1):
        sum[i]=sum[i+1]+int(num[i])*dd[i]

    for i in range(1,cnt+1):
        res = 0
        len = 0
        for j in range(0,k+1):
            xx = lens[i][j]
            if(xx==0):
                continue
            res = res+(sum[len+1]-sum[len+xx+1])//(10**(len))
            len += xx
        ans=min(ans,res)
    print(ans)

    for i in range(0,n+3):
        sum[i]=dd[i]=0


if __name__ == "__main__":
    t = int(input())
    for i in range(0,t):
        main()