func_code_string: #include <bits/stdc++.h>   using namespace std;   int N, M, i, j;   int a, b, v[105];   bool ok = true;   int main() {     cin >> N >> M;     for (i = 1; i <= N; i++) {       cin >> a >> b;       a++;       v[a]++;       v[b + 1]--;     }     for (i = 1; i <= M; i++) {       v[i] += v[i - 1];       if (v[i] == 0) ok = false;     }     if (ok == true)       cout <<  YES ;     else       cout <<  NO ;     return 0;   }   