#include<cstdio>
#include<vector>
#include<queue>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<set>
#include<map>
#include<ctime>
#include<random>
#include<array>
#include<assert.h>
#include<bitset>
#define pb emplace_back
#define mp make_pair
#define fi first
#define se second
#define dbg(x) cerr<<"In Line "<< __LINE__<<" the "<<#x<<" = "<<x<<'\n'
#define dpi(x,y) cerr<<"In Line "<<__LINE__<<" the "<<#x<<" = "<<x<<" ; "<<"the "<<#y<<" = "<<y<<'\n'
#define DE(fmt,...) fprintf(stderr, "Line %d : " fmt "\n",__LINE__,##__VA_ARGS__)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned short us;
typedef pair<int,int>pii;
typedef pair<ll,int>pli;
typedef pair<ll,ll>pll;
typedef pair<int,ll>pil;
typedef vector<int>vi;
typedef vector<ll>vll;
typedef vector<pii>vpii;
typedef vector<pll>vpll;
template<typename T>T cmax(T &x, T y){return x=x>y?x:y;}
template<typename T>T cmin(T &x, T y){return x=x<y?x:y;}
template<typename T>
T &read(T &r){
	r=0;bool w=0;char ch=getchar();
	while(ch<'0'||ch>'9')w=ch=='-'?1:0,ch=getchar();
	while(ch>='0'&&ch<='9')r=r*10+(ch^48),ch=getchar();
	return r=w?-r:r;
}
template<typename T1,typename... T2>
void read(T1 &x,T2& ...y){read(x);read(y...);}
const int N=260;
int n,crt[300][300];
int solve1(vpii &vec){
	vi p={3,5,17};
	vi s={0,0,0};
	for(int o=0;o<3;o++){
		int w=0;
		for(auto [x,y]:vec)w=(w+1ll*x*y%p[o])%p[o];
		if(w){
			int k=1;
			for(int i=1;i<=n;i++){
				k=1ll*k*i%(p[o]-1);
				if(!k)break;
			}
			s[o]=1;
			for(int i=1;i<=k;i++)s[o]=s[o]*w%p[o];
		}
	}
	for(int i=0;i<255;i++)
		if(i%p[0]==s[0] && i%p[1]==s[1] && i%p[2]==s[2])
			return i;
	assert(0);
	return -1;
}
int bit(int x){return 1<<x;}
bitset<257>f[510];
int solve2(vpii &vec){
	if(n<=11){
		vi a;
		for(auto [x,y]:vec)while(y--)a.pb(x);
		int s=1;
		for(int S=0;S<bit(n);S++)if(__builtin_popcount(S)==n/2){
			int w=0;
			for(int i=0;i<n;i++){
				if(bit(i)&S)
					w=(w-a[i]%257+257)%257;
				else
					w=(w+a[i]%257)%257;
			}
			s=s*w%257;
		}
		int k=1;
		for(int i=1;i<=n/2;i++)k=k*i%256;
		for(int i=1;i<=(n+1)/2;i++)k=k*i%256;
		int ans=0;
		if(s){
			ans=1;
			for(int i=1;i<=k;i++)ans=ans*s%257;
		}
		return ans;
	}
	else{
		sort(vec.begin(),vec.end(),[](pii &x,pii &y){return	x.se>y.se;});
		if(n<512 || n-vec[0].se<256){
			for(int i=0;i<=257;i++)f[i].reset();
			f[0][0]=1;
			auto up=[&](bitset<257>a,int x){
				x=x%257;
				if(x==0)return a;
				return (a<<x)|(a>>(257-x));
			};
			int c=0;
			for(auto [x,y]:vec)if(x!=vec[0].fi){
				while(y--){
					for(int i=c+1;i>=1;i--)
						f[i]=up(f[i],257-x)|up(f[i-1],x);
					f[0]=up(f[0],257-x);
					++c;
				}
			}
			int k=(n+1)/2;
			for(int i=0;i<=min(c,k);i++){
				for(int j=0;j<257;j++)
					if(f[i][j] && vec[0].se>=k-i){
						int w=(j+1ll*(k-i)*vec[0].fi-1ll*(vec[0].se-(k-i))*vec[0].fi)%257;
						w=(w+257)%257;
						if(w==0)return 0;
					}
			}
			return 1;
		}
		return 0;
	}
}
void solve(){
	int m;read(m);n=0;
	vpii vec;
	for(int i=1,x,y;i<=m;i++)read(x,y),vec.pb(x,y),n+=y;
	cout<<crt[solve1(vec)][solve2(vec)]<<'\n';
}
signed main(){
	#ifdef do_while_true
		assert(freopen("data.in","r",stdin));
//		assert(freopen("data.out","w",stdout));
	#endif
	for(int i=0;i<65535;i++)crt[i%255][i%257]=i;
	int T;read(T);
	while(T--)solve();
    #ifdef do_while_true
//		cerr<<'\n'<<"Time:"<<1.0*clock()/CLOCKS_PER_SEC*1000<<" ms"<<'\n';
	#endif
	return 0;
}