View Compilation Error

0_0_29382635_14614.cpp: In function 'int main()':
0_0_29382635_14614.cpp:62:39: error: 's' was not declared in this scope
         for (int i = 1; i <= N; i++) {s
                                       ^
0_0_29382635_14614.cpp:67:25: error: 'u' was not declared in this scope
                 int v = u-3;
                         ^
0_0_29382635_14614.cpp:71:25: error: 'u' was not declared in this scope
                 int v = u+1;
                         ^