View Compilation Error

0_0_31417761_20227.cpp: In function 'int main()':
0_0_31417761_20227.cpp:23:34: error: 'class std::set<int>' has no member named 'ins'
   for(int i = n; i <= m; ++ i) s.ins
                                  ^
0_0_31417761_20227.cpp:23:34: error: expected '}' at end of input
0_0_31417761_20227.cpp:23:34: error: expected '}' at end of input