View Compilation Error

0_0_36651010_15589.cpp: In function 'int main()':
0_0_36651010_15589.cpp:62:16: error: conflicting declaration 'auto it'
           auto it = s[i].upper_bound(n); it--;
                ^
0_0_36651010_15589.cpp:60:16: note: previous declaration as 'std::_Rb_tree_const_iterator<long long int> it'
           auto it = s[i].begin();
                ^