View Compilation Error

0_0_37659501_18636.cpp:15:1: error: 'set' does not name a type
 set < int > jihe ;
 ^
0_0_37659501_18636.cpp: In function 'int main()':
0_0_37659501_18636.cpp:23:34: error: 'jihe' was not declared in this scope
         Case ++ , jihe_cnt = n , jihe.clear () ;
                                  ^