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

#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,b,a) for(int i=b;i>=a;i--)
#define fori(i,a) for(auto i : a )
#define all(a) begin(a), end(a)
#define mset(a,b) memset(a,b,sizeof(a))
#define mcopy(a,b) memcopy(a,b,sizeof(a))
#define ll long long
ll func(ll v){
  ll r = 0;
  while (v >>= 1) {
      r++;
  }
  return  r;
}
void solve(){
  ll x,y;
  cin>>x>>y;
  int flag1=0,flag2=0;
  if(x<0) flag1=1;
  if(y<0) flag2=1;
  x=abs(x);
  y=abs(y);
  string ans="";

  for(int i=0;i<64;i++){
    ll z=func(x),l=func(y);
    if(z<i && l<i) break;
    // if(x==0 && y==0) break;
    if(x<(1<<i) && (y<(1<<i))){
      cout<<"IMPOSSIBLE"<<endl;
      return ;
    }

    if((x&(1<<i)== (y&(1<<i)))){
      cout<<"IMPOSSIBLE"<<endl;
      return ;
    }
    else if( (x&(1<<i))==0 && (y&(1<<i))==(1<<i) ){

      if( (x &(1<<(i+1)))== (y & (1<<(i+1))) && z>i){
        y+=(1<<i);
        ans+="S";
      }
      else if(z>i){
        ans+="N";
        y-=(1<<i);
      }
      else if(z<=i){
        if((y & (1<<(i+1)))==0 && l>i){
          y+=(1<<i);
          ans+="S";
        }
        else{
          ans+="N";
          y-=(1<<i);
        }
      }
    }
    else if( (x&(1<<i))==(1<<i) && (y&(1<<i))==0 ){
      // cout<<1<<endl;
      if( (x&(1<<(i+1)))== (y&(1<<(i+1))) && l>i){
        x+=(1<<i);
        ans+="W";
        // cout<<1<<endl;
      }
      else if(l>i){
        x-=(1<<i);
        ans+="E";
        // cout<<2<<endl;
      }
      else if(l<=i){
        if((x&(1<<(i+1)))==0 && z>i){
          x+=(1<<i);
          ans+="W";
          // cout<<3<<endl;
        }
        else{
          x-=(1<<i);
          ans+="E";
          // cout<<4<<endl;
        }
      }

    }
    // cout<<x<<" "<<y<<endl;

  }

  if(flag1){
    rep(i,0,ans.length()) {
      if(ans[i]=='S') ans[i]='N';
      else if(ans[i]=='N') ans[i]='S';
    }
  }
  if(flag2){
    rep(i,0,ans.length()) {
      if(ans[i]=='W') ans[i]='E';
      else if(ans[i]=='E') ans[i]='W';
    }
  }
  cout<<ans<<endl;
}

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

//   freopen("input.txt", "r", stdin);
  // freopen("output.txt", "w", stdout);

  int t,k=1;
  cin>>t;
  while(t--){
    cout<<"Case #"<<k++<<": ";
    solve();
  }
}