View Compilation Error

0_0_14227064_6541.cpp: In function 'int main()':
0_0_14227064_6541.cpp:38:50: error: 'len' was not declared in this scope
                      for(int ii=i,jj=j; ii<n&&jj<len&&(a[ii][jj]=='R'|| a[ii][jj]=='G'); ii++,jj++)
                                                  ^