View Compilation Error

0_0_13026976_6767.cpp: In function `int dfs(int, int)':
0_0_13026976_6767.cpp:12: error: `z' undeclared (first use this function)
0_0_13026976_6767.cpp:12: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_13026976_6767.cpp: In function `int main()':
0_0_13026976_6767.cpp:26: error: `z' undeclared (first use this function)
0_0_13026976_6767.cpp:30: error: expected `)' before ';' token