View Compilation Error

0_0_11860579_18406.cpp: In function `int main()':
0_0_11860579_18406.cpp:6: error: `N' undeclared (first use this function)
0_0_11860579_18406.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_11860579_18406.cpp:7: error: `sum' undeclared (first use this function)