t = int(input())
for i in range(t):
x = i
n = int(input())
s = input()
qianzui = [0]*(n+1)
for i in range(n):
qianzui[i+1] = int(s[i])+qianzui[i]
len_l = int(n/2+0.5)
res =0
ans = 0
left = 0
right = left+len_l
while right<=n:
ans = qianzui[right]-qianzui[left]
res =max(ans,res)
left+=1
right =left+len_l
print("Case #%d: %d"%(x+1,res)