#include<bits/stdc++.h>
using namespace std;
typedef long long ll; typedef array<int,2> pr;
const int MAXN = 30,MAXM = 600,M = 256;
int T,k,n;

pr w[MAXM];

namespace T1{
    const int mod = 255,phi = 128;
    int solve(){
        int sum = 0;
        for(int i=1;i<=M;i++)sum = (sum + 1ll*w[i][0]*w[i][1]%mod)%mod;
        int fac = 1; if(n >= phi)fac = 0; else for(int i=1;i<=n;i++)fac = fac*i%mod;
        if(n > 5)fac += phi;
        int pw = 1; while(fac--)pw = pw*sum%mod; return pw;
    }
}
namespace T2{
    const int mod = 257,phi = 256;
    int N,buc[mod];
    int solve(){
        N = n/2; //选N个位置base 256,n-N个位置base 1
        memset(buc,0,sizeof buc);
        if(n<12){
            int arr[30] = {}; n = 0;
            for(int i=1;i<=M;i++)while(w[i][0]--)arr[n++] = w[i][1];
            int w = 1; 
            for(int i=1;i<=N;i++)w = w*i%phi;
            for(int i=1;i<=n-N;i++)w = w*i%phi;

            for(int S=0;S<(1<<n);S++){
                int pcnt = __builtin_popcount(S); if(pcnt != N)continue;
                int sum = 0; 
                for(int i=0;i<n;i++){
                    if(S>>i&1)sum = (sum-arr[i]+mod)%mod;
                    else sum = (sum+arr[i])%mod;
                }
                buc[sum] = (buc[sum] + w)%phi;
            }
            int res = 1;
            for(int i=0;i<mod;i++)while(buc[i]--)res = res*i%mod;
            return res;
        }else return 0;
    }
}

void solve(){
    for(int i=1;i<=M;i++)w[i][0] = 0,w[i][1] = i-1; n = 0;
    cin>>k;
    while(k--){
        int x,c; cin>>x>>c; n += c; w[x+1][0] = c;
    }
    sort(w+1,w+1+M);
    
    int ans_255 = T1::solve(),ans_257 = T2::solve();
    int ans = ans_257; while(ans % 255 != ans_255)ans += 257;
    cout<<ans<<endl;
}

int main(){
    cin>>T;
    while(T--)solve();

    return 0;
}