View Compilation Error

0_0_29685266_21028.cpp: In function 'int main()':
0_0_29685266_21028.cpp:6:7: error: 'N' was not declared in this scope
  cin>>N;
       ^
0_0_29685266_21028.cpp:11:9: error: 'a' was not declared in this scope
    cin>>a>>b;
         ^