View Compilation Error

0_0_21293131_20791.cpp: In function 'll pwr(ll, ll, ll)':
0_0_21293131_20791.cpp:62:36: error: 'powmod' was not declared in this scope
         return a*powmod(a*a%p,x/2,p)%p;
                                    ^
0_0_21293131_20791.cpp:64:34: error: 'powmod' was not declared in this scope
         return powmod(a*a%p,x/2,p)%p;
                                  ^