#include using namespace std; using ll = long long; template using Pa = pair; template using vec = vector; template using vvec = vector>; constexpr ll mod = 1000000007; struct mint { ll x; mint(ll x=0):x((x%mod+mod)%mod){} friend ostream &operator<<(ostream& os,const mint& a){ return os << a.x; } friend istream &operator>>(istream& is,mint& a){ ll t; is >> t; a = mint(t); return (is); } mint& operator+=(const mint a) { if ((x += a.x) >= mod) x -= mod; return *this; } mint& operator-=(const mint a) { if ((x += mod-a.x) >= mod) x -= mod; return *this; } mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this; } mint operator+(const mint a) const { mint res(*this); return res+=a; } mint operator-(const mint a) const { mint res(*this); return res-=a; } mint operator*(const mint a) const { mint res(*this); return res*=a; } mint pow(ll t) const { if (!t) return 1; mint a = pow(t>>1); a *= a; if (t&1) a *= *this; return a; } // for prime mod mint inv() const { return pow(mod-2); } mint& operator/=(const mint a) { return (*this) *= a.inv(); } mint operator/(const mint a) const { mint res(*this); return res/=a; } }; int main(){ cin.tie(0); ios::sync_with_stdio(false); int N,M; cin >> N >> M; vec V(N),R(M); for(int i=0;i> V[i]; for(int i=0;i> R[i]; ll A,B; cin >> A >> B; int ma = 100000; vec dp(ma+1); dp[0] = 1; for(int i=0;i ndp(ma+1); for(int j=0;j<=ma;j++){ ndp[j] += dp[j]; if(j+V[i]<=ma) ndp[j+V[i]] += dp[j]; } dp.swap(ndp); } for(int i=0;i rdp(ma+1); rdp[0] = 1; for(int i=0;i ndp(ma+1); for(int j=0;j<=ma;j++){ ndp[j] += rdp[j]; if(j+R[i]<=ma) ndp[j+R[i]] += rdp[j]; } rdp.swap(ndp); } mint ans = 0; for(ll i=1;i<=ma;i++){ ll l = A*i,r = min((ll) ma,B*i); if(l>ma) continue; ans += (dp[r]-dp[l-1])*rdp[i]; } cout << ans << "\n"; }