/in/foo.cc:13:4: error: expected initializer before 'n'
   13 | ll n;
      |    ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:17:16: error: 'n' was not declared in this scope; did you mean 'yn'?
   17 |         cin >> n;
      |                ^
      |                yn
/in/foo.cc:22:53: error: invalid types 'll {aka long long int}[int]' for array subscript
   22 |                 if(a[i].s >= last) ans++, last = ans[i].e;
      |                                                     ^