View Compilation Error

0_0_30050517_12252.cpp: In function 'int main()':
0_0_30050517_12252.cpp:22:30: error: '__gnu_cxx::__alloc_traits<std::allocator<std::pair<int, int> > >::value_type' has no member named 'size'
         for(int i=0;i<pos[i].size();i++){
                              ^