View Compilation Error

0_0_17288549_26254.cpp: In function 'int main()':
0_0_17288549_26254.cpp:10:24: error: 'M_PI' was not declared in this scope
   ans=0.5*ceil(log10(2*M_PI*n))+ceil(n*log10(n/M_E));
                        ^
0_0_17288549_26254.cpp:10:48: error: 'M_E' was not declared in this scope
   ans=0.5*ceil(log10(2*M_PI*n))+ceil(n*log10(n/M_E));
                                                ^