View Compilation Error

0_0_26832298_21448.cpp: In function 'void prime()':
0_0_26832298_21448.cpp:20:34: error: void value not ignored as it ought to be
     for(int i=1;i<maxn;i++)sum[i]=mod(sum[i-1]+phi[i]);
                                  ^
0_0_26832298_21448.cpp: In function 'int f(int, int)':
0_0_26832298_21448.cpp:29:62: error: void value not ignored as it ought to be
          return mod((ll)phi[p[i]]*f(N/p[i],M)%Mod+f(N,M/p[i]));
                                                              ^
0_0_26832298_21448.cpp:31:48: error: void value not ignored as it ought to be
     return mod((ll)phi[N]*f(N/N,M)%Mod+f(N,M/N));
                                                ^