//#include #include // cout, endl, cin #include // string, to_string, stoi #include // vector #include // min, max, swap, sort, reverse, lower_bound, upper_bound #include // pair, make_pair #include // tuple, make_tuple #include // int64_t, int*_t #include // printf #include // map #include // queue, priority_queue #include // set #include // stack #include // deque #include // unordered_map #include // unordered_set #include // bitset #include // isupper, islower, isdigit, toupper, tolower #include #include using namespace std; //using namespace atcoder; #define rep(i, n) for (int i = 0; i < (int)(n); i++) #define repi(i, a, b) for (int i = (int)(a); i < (int)(b); i++) typedef long long ll; typedef unsigned long long ull; const ll inf=1e18; using graph = vector > ; using P= pair; using vi=vector; using vvi=vector; using vll=vector; using vvll=vector; using vp=vector

; using vpp=vector; using vd=vector; using vvd =vector; //string T="ABCDEFGHIJKLMNOPQRSTUVWXYZ"; //string S="abcdefghijklmnopqrstuvwxyz"; //g++ main.cpp -std=c++17 -I . //cout < par, siz; UnionFind(int n) : par(n, -1) , siz(n, 1) { } int root(int x) { if (par[x] == -1) return x; else return par[x] = root(par[x]); } bool issame(int x, int y) { return root(x) == root(y); } bool unite(int x, int y) { x = root(x), y = root(y); if (x == y) return false; if (siz[x] < siz[y]) swap(x, y); par[y] = x; siz[x] += siz[y]; return true; } int size(int x) { return siz[root(x)]; } }; ll gcd(ll x,ll y){ if(y==0)return x; return gcd(y,x%y); } ll lcm(ll x,ll y){ return ll(x/gcd(x,y))*y; } template bool chmin(T& a, T b) { if (a > b) { a = b; return true; } else return false; } template bool chmax(T& a, T b) { if (a < b) { a = b; return true; } else return false; } // https://youtu.be/L8grWxBlIZ4?t=9858 // https://youtu.be/ERZuLAxZffQ?t=4807 : optimize // https://youtu.be/8uowVvQ_-Mo?t=1329 : division const ll mod =998244353; struct mint { ll x; // typedef long long ll; mint(ll x=0):x((x%mod+mod)%mod){} mint operator-() const { return mint(-x);} 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 { return mint(*this) += a;} mint operator-(const mint a) const { return mint(*this) -= a;} mint operator*(const mint a) const { return mint(*this) *= 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 { return mint(*this) /= a;} }; istream& operator>>(istream& is, const mint& a) { return is >> a.x;} ostream& operator<<(ostream& os, const mint& a) { return os << a.x;} // combination mod prime // https://www.youtube.com/watch?v=8uowVvQ_-Mo&feature=youtu.be&t=1619 struct combination { vector fact, ifact; combination(int n):fact(n+1),ifact(n+1) { //assert(n < mod); fact[0] = 1; for (int i = 1; i <= n; ++i) fact[i] = fact[i-1]*i; ifact[n] = fact[n].inv(); for (int i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i; } mint operator()(int n, int k) { if (k < 0 || k > n) return 0; return fact[n]*ifact[k]*ifact[n-k]; } mint p(int n, int k) { return fact[n]*ifact[n-k]; } } c(2000005); using vm=vector ; using vvm=vector ; ll sqrt_(ll x) { ll l = 0, r = ll(3e9)+1; while (l+1=0 && y>=0 && x struct Matrix { int h, w; vector > d; Matrix() {} Matrix(int h, int w, T val=0): h(h), w(w), d(h, vector(w,val)) {} Matrix& unit() { //assert(h == w); rep(i,h) d[i][i] = 1; return *this; } const vector& operator[](int i) const { return d[i];} vector& operator[](int i) { return d[i];} Matrix operator*(const Matrix& a) const { //assert(w == a.h); Matrix r(h, a.w); rep(i,h)rep(k,w)rep(j,a.w) { r[i][j] += d[i][k]*a[k][j]; } return r; } Matrix pow(ll t) const { // assert(h == w); if (!t) return Matrix(h,h).unit(); if (t == 1) return *this; Matrix r = pow(t>>1); r = r*r; if (t&1) r = r*(*this); return r; } }; //g++ main.cpp -std=c++17 -I . ll extgcd(ll a,ll b,ll &x,ll &y){ ll d=a; if(b!=0){ d=extgcd(b,a%b,y,x); y-=(a/b)*x; } else{ x=1;y=0; } return d; } ll mod_inverse(ll a,ll m){ ll x,y; extgcd(a,m,x,y); return (m+x%m)%m; } P linear_congruence(vll &A,vll &B,vll &M){ ll x=0,m=1; rep(i,A.size()){ ll a=A[i]*m,b=B[i]-A[i]*x,d=gcd(M[i],a); if(b%d)return P(0,-1); ll t=(b/d)*mod_inverse(a/d,M[i]/d)%(M[i]/d); x=x+m*t; m*=M[i]/d; } return P((x%m+m)%m,m); } int main(){cin.tie(0);ios::sync_with_stdio(false); int n,m; cin >> n>> m; vll a(m,1),b(m),M(m); rep(i,m)cin >> M[i] >> b[i]; P res=linear_congruence(a,b,M); if(res.second==-1){ cout << "NaN" << endl; return 0; } res.first=(res.first+res.second)%res.second; if(res.first>n)cout << "NaN"; else cout << res.first <