/in/foo.cc: In function 'void work()':
/in/foo.cc:65:11: error: 'INT_MAX' was not declared in this scope
  int R = -INT_MAX,ans = 0;
           ^~~~~~~
/in/foo.cc:68:4: error: 'ans' was not declared in this scope
    ans += p[i].r - p[i].l;
    ^~~
/in/foo.cc:71:4: error: 'ans' was not declared in this scope
    ans += p[i].r - p[i-1].r;
    ^~~
/in/foo.cc:75:16: error: 'ans' was not declared in this scope
  printf("%d\n",ans);
                ^~~