View Compilation Error

0_0_22706919_7897.cpp: In function 'long long int solve(long long int, long long int)':
0_0_22706919_7897.cpp:33:24: error: 'euler' was not declared in this scope
      ans=(ans+euler(n/i)*s())%mod;
                        ^
0_0_22706919_7897.cpp:33:28: error: 's' was not declared in this scope
      ans=(ans+euler(n/i)*s())%mod;
                            ^
0_0_22706919_7897.cpp:36:28: error: 'S' was not declared in this scope
        ans=(ans+euler(i)*S())%mod;
                            ^