View Compilation Error

0_0_30134866_9931.cpp: In function 'll qmul(ll, ll, ll)':
0_0_30134866_9931.cpp:16:28: error: 'p' was not declared in this scope
         if(b&1)res=(res+a)%p;
                            ^
0_0_30134866_9931.cpp:17:17: error: 'p' was not declared in this scope
         a=(a+a)%p;
                 ^