#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e6+5;
char s[maxn];
typedef long long ll;
ll k;
int main()
{
int _;
cin>>_;
int ca = 1;
while(_--)
{
scanf("%lld",&k);
scanf("%s",s);
if(k==0)
{
printf("Case #%d: 0\n",ca++);
continue;
}
ll len = strlen(s);
ll sum = 0;
ll ans = 0;
ll l = 0,r = 0;
while(r < len && r-l+1 <=k)
{
ll cha = (1 << (r-l));
ans += 1ll*(s[r]-'0')*cha;
r++;
}
sum = ans;
while(r < len)
{
while(r - l + 1 <= k)
{
sum += (s[r]-'0');
r++;
}
ans = max(sum,ans);
if(r>=len)
break;
ll res = (1 << (k-1));
sum -= 1ll*(s[l] - '0')*res;
sum *= 2;
l++;
}
printf("Case #%d: %lld\n",ca++,ans);
}
return 0;
}