#include #pragma GCC optimize("Ofast") using namespace std; using std::cout; using std::cin; using std::endl; using ll=long long; using ld=long double; ll I=1167167167167167167; ll Q=1e9+7; #define rep(i,a) for (ll i=0;i using _pq = priority_queue, greater>; template ll LB(vector &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();} template ll UB(vector &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();} template bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;} template bool chmax(T &a,const T &b){if(a void So(vector &v) {sort(v.begin(),v.end());} template void Sore(vector &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});} template void print_tate(vector &v) {rep(i,v.size()) cout<>N>>M; vector> p(M); rep(i,M){ int l,r; cin>>l>>r; p[i]={r,l}; } So(p); int now=-1; rep(i,M){ if(p[i].second>now){ N--; now=p[i].first; } } cout<