View Compilation Error

0_0_30374519_28477.cpp: In function 'int main()':
0_0_30374519_28477.cpp:20:18: error: 'a' was not declared in this scope
             cin>>a[i]>>b[i];
                  ^
0_0_30374519_28477.cpp:20:24: error: 'b' was not declared in this scope
             cin>>a[i]>>b[i];
                        ^
0_0_30374519_28477.cpp:24:22: error: 'a' was not declared in this scope
             ans^=dfs(a[i],b[i]);
                      ^
0_0_30374519_28477.cpp:24:27: error: 'b' was not declared in this scope
             ans^=dfs(a[i],b[i]);
                           ^