View Compilation Error

0_0_26269450_21932.cpp: In function 'int main()':
0_0_26269450_21932.cpp:131:81: error: 'get_inv' was not declared in this scope
    s*=(fastpow(fac[i].first,n*fac[i].second+1,250*k)-1)*get_inv(fac[i].first-1,k);
                                                                                 ^