poj 2665

//poj 2665 小学生题 种树题 #include <iostream>#include <algorithm>#include <math.h>#include <string> using namespace std;int main(){int n, m;cin>>n;cin>>m;while( n != 0 && m != 0){int start, end;n = n+1;for(int i = 0; i < m; i++){cin>>start>>end;n -= (end - start + 1);}cout<<n<<endl;cin>>n;cin>>m;}return 0;}