View Compilation Error

0_0_31082328_20468.cpp: In function 'long long int F(long long int, long long int)':
0_0_31082328_20468.cpp:38:44: error: 'GetPhi' was not declared in this scope
  return qpow((N % 10), F(N / 10, GetPhi(mod)), mod);
                                            ^