View Compilation Error

0_0_23166072_25080.cpp: In function 'int main()':
0_0_23166072_25080.cpp:53:26: error: 'a11' was not declared in this scope
             sum=a11(a,n,i);
                          ^
0_0_23166072_25080.cpp:66:26: error: 'a22' was not declared in this scope
             sum=a22(a,m,j);
                          ^