#include 
    
     using namespace std;typedef long long LL;const int N=1e2+10;int main(){    int T,cas=1,n,x;    scanf("%d",&T);    while(T--)    {        scanf("%d",&n);        int up=0;        int down=n;        for(int i=1;i<=n;i++)        {            scanf("%d",&x);            up+=abs(x);            if(x<0)                down--;        }        if(!down)            printf("Case %d: inf\n",cas++);        else        {            int g=__gcd(up,down);            printf("Case %d: %d/%d\n",cas++,up/g,down/g);        }    }    return 0;}