#include<bits/stdc++.h>

#define rep(i,a,b) for(int i=a;i<=b;i++)

using namespace std;

int a[][],ans[];

int Guass(int N)

{

    int res=;

    rep(i,,N-){

        int mark=i;

        rep(j,i+,N-) if(abs(a[j][i])>abs(a[mark][i])) mark=j;

        if(mark!=i) rep(j,,N) swap(a[i][j],a[mark][j]);

        if(!a[i][i]){ res++; continue;} //自由元

        rep(j,i+,N){

           if(!a[j][i]) continue;

           rep(k,i,N){

               a[j][k]^=a[i][k];

           }

        }

    }

    for(int i=N-;i>=;i--){

        if(!a[i][i]&&a[i][N]) return -;//无解

        ans[i]=a[i][N]&a[i][i];

        rep(j,,i-) a[j][N]^=(a[j][i]&ans[i]);

    }

    return <<res;

}

int s[],t[],res;

int main()

{

    int T,N,u,v;

    scanf("%d",&T);

    while(T--){

        memset(a,,sizeof(a));

        scanf("%d",&N);

        rep(i,,N-) scanf("%d",&s[i]);

        rep(i,,N-) scanf("%d",&t[i]);

        rep(i,,N-) a[i][N]=s[i]^t[i],a[i][i]=;

        while(~scanf("%d%d",&u,&v)&&u+v!=){

            a[v-][u-]=; //二者不要写反

        }

        int res=Guass(N);

        if(res==-) puts("Oh,it's impossible~!!");

        else printf("%d\n",res);

    }

    return ;

}