View Compilation Error

0_0_4411846_2535.cpp: In function `void addEdge(int, int, int)':
0_0_4411846_2535.cpp:17: error: `a' undeclared (first use this function)
0_0_4411846_2535.cpp:17: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4411846_2535.cpp: In function `int main()':
0_0_4411846_2535.cpp:94: error: `m' undeclared (first use this function)