#include<bits/stdc++.h>
using namespace std;

#define FAST ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>

#define int long long
#define double long double

#define all(a)      (a).begin(),(a).end()
#define sz(x)       (int)x.size()

#define ff first
#define ss second
#define mp make_pair

#define pb push_back
#define endl "\n"

#define f(i,l,r) for(int i=l;i<=r;i++)
#define rf(i,r,l) for(int i=r;i>=l;i--)

#define bp __builtin_popcountll
#define inf 3e15

const int N=1e5+5;
const int M=1e9+7;

void solve()
{
    int x,y;
    cin>>x>>y;
    int p=abs(x-0);
    int q=abs(y-0);
    p=p%2;
    q=q%2;
    if(p==q)
    {
        cout<<"IMPOSSIBLE"<<endl;
        return;
    }
    p=abs(x-0);
    q=abs(y-0);

    int sum=0,id=-1;
    for(int i=1;;i*=2)
    {
        sum+=i;
        int oo=sum-p-q;
        oo/=2;
        if((sum-p-q)>=0)
        {
            id=sum;
            break;
        }
    }
    if(sum==p+q)
    {
        for(int i=1;i<=sum;i*=2)
        {
            if(p&i)
            {
                if(x<0)
                cout<<"W";
                else
                cout<<"E";
            }
            else
            {
                if(y<0)
                cout<<"S";
                else
                cout<<"N";
            }
        }
        cout<<endl;
        return;
    }
    else
    {
        int tt=sum-p-q;
        tt/=2;
        int f1=0,f2=0;
        for(int i=0;i<=tt;i++)
        {
            if(((p+i)^(q+tt-i)^i^(tt-i))==sum)
            {
                f1=i;
                f2=tt-i;
                break;
            }
        }
        string ans="";
        p+=f1;
        q+=f2;
                int cnt=0;
            for(int i=1;i<=sum;i*=2)
            {
                cnt++;
                if(p&i)
                {
                    if(x<0)
                    ans+='W';
                    else
                    ans+='E';
                }
                else if(q&i)
                {
                    if(y<0)
                    ans+='S';
                    else
                    ans+='N';
                }
                else if(f1&i)
                {
                    if(x<0)
                    ans+='E';
                    else
                    ans+='W';
                }
                else
                {
                    if(y<0)
                    ans+='N';
                    else
                    ans+='S';
                }

            }
            cout<<ans<<endl;
            return;
    }
}
signed main()
{
    FAST
    int t=1;
    cin>>t;
    for(int tc=1;tc<=t;tc++)
    {
        cout<<"Case #"<<tc<<": ";
        solve();
    }
}