View Compilation Error

0_0_8448158_12987.cpp: In function `int dfs(int, int, int)':
0_0_8448158_12987.cpp:13: error: `abs' undeclared (first use this function)
0_0_8448158_12987.cpp:13: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_8448158_12987.cpp: In function `int main()':
0_0_8448158_12987.cpp:64: error: expected `}' at end of input