View Compilation Error

0_0_37755076_24320.cpp: In function 'void sl()':
0_0_37755076_24320.cpp:22:23: error: '__gnu_cxx::__alloc_traits<std::allocator<std::pair<int, int> > >::value_type' has no member named 'firts'
   while(it >= pp[cur].firts && cur < n){
                       ^