View Compilation Error

0_0_6725430_21836.cpp: In function `void solve()':
0_0_6725430_21836.cpp:30: error: `M' undeclared (first use this function)
0_0_6725430_21836.cpp:30: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6725430_21836.cpp:38: error: `insert' undeclared (first use this function)
0_0_6725430_21836.cpp:39: error: `N' undeclared (first use this function)