View Compilation Error

0_0_22417049_20697.cpp: In function 'int main()':
0_0_22417049_20697.cpp:42:52: error: 'a' was not declared in this scope
     else if(p[i+2]>=p[i+4]&&p[i+3]>=p[i+1]&&p[i+4]+a[i]>=p[i+2]&&p[i+5]+p[i+1]>=p[i+3]) f =i+5;
                                                    ^