//Let's join Kaede Takagaki Fan Club !! #pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define int long long //#define L __int128 typedef long long ll; typedef pair P; typedef pair P1; typedef pair P2; #define pu push #define pb push_back #define eb emplace_back #define mp make_pair #define eps 1e-7 #define INF 1000000000 #define a first #define b second #define fi first #define sc second #define rng(i,a,b) for(int i=(int)(a);i<(int)(b);i++) #define rep(i,x) for(int i=0;i bool chmax(t&a,u b){if(a bool chmin(t&a,u b){if(b using vc=vector; template ostream& operator<<(ostream& os,const pair& p){ return os<<"{"< ostream& operator<<(ostream& os,const vc& v){ os<<"{"; for(auto e:v)os<> 30)) * 0xbf58476d1ce4e5b9; x = (x ^ (x >> 27)) * 0x94d049bb133111eb; return x ^ (x >> 31); } size_t operator()(uint64_t x) const { static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count(); return splitmix64(x + FIXED_RANDOM); } size_t operator()(pair x)const{ return operator()(uint64_t(x.first)<<32|x.second); } }; //unordered_set -> dtype, null_type //unordered_map -> dtype(key), dtype(value) using namespace __gnu_pbds; template using hash_table=gp_hash_table; template void g(T &a){ cin >> a; } template void o(const T &a,bool space=false){ cout << a << (space?' ':'\n'); } //ios::sync_with_stdio(false); const ll mod = 1000000007; mt19937_64 mt(chrono::steady_clock::now().time_since_epoch().count()); template void add(T&a,T b){ a+=b; if(a >= mod) a-=mod; } ll modpow(ll x,ll n){ ll res=1; while(n>0){ if(n&1) res=res*x%mod; x=x*x%mod; n>>=1; } return res; } #define _sz 1 ll F[_sz],R[_sz]; void make(){ F[0] = 1; for(int i=1;i<_sz;i++) F[i] = F[i-1]*i%mod; R[_sz-1] = modpow(F[_sz-1], mod-2); for(int i=_sz-2;i>=0;i--) R[i] = R[i+1] * (i+1) % mod; } ll C(int a,int b){ if(b < 0 || a < b) return 0; return F[a]*R[b]%mod*R[a-b]%mod; } int dp[3005][3005][2]; vc

st; void solve(){ int n; cin >> n; rep(i, n){ int t, x; cin >> t >> x; st.eb(x-t, t); } SORT(st); dp[0][0][0] = 1; rep(i, st.size()){ int ty = st[i].b; int val = st[i].a; rep(j, i+1){ rep(k, 2){ if(dp[i][j][k] == 0) continue; if(ty == 1) add(dp[i+1][j][k], dp[i][j][k]); if(val > j) add(dp[i+1][j+1][k^ty], dp[i][j][k] * (val-j) % mod); } } } //dp[n][*][0] - dp[n][*][1] int ans = 0; rep(i, n+1){ int x = dp[n][i][0] - dp[n][i][1]; repn(j, n-i) x = x * j % mod; add(ans, (x+mod)%mod); } o(ans); } signed main(){ cin.tie(0); ios::sync_with_stdio(0); cout<> t; while(t--) solve(); }