procedure euler; var  i,j:longint;   begin     phi[1]:=1;     for i:=2 to n do       begin         if not mark[i] then           begin             inc(tot);             p[tot]:=i;             phi[i]:=i-1;           end;         for j:=1 to n do           begin             if i*p[j]>n then break;             mark[i*p[j]]:=true;             if i mod p[j]=0 then               begin                 phi[i*p[j]]:=phi[i]*p[j];                 break;               end else phi[i*p[j]]:=phi[i]*(p[j]-1);           end;       end;   end;

 c++

void euler(){       b[1]=1;phi[1]=1;       for (LL i=2;i<=n;i++){            if (b[i]==0) {ss[++cnt]=i;phi[i]=i-1;}                        for (LL j=1;j<=cnt;j++){                  if (i*ss[j]>n) break;                  b[i*ss[j]]=1;                  if (i%ss[j]==0) {phi[i*ss[j]]=phi[i]*ss[j];break;}              else phi[i*ss[j]]=phi[i]*(ss[j]-1);            }       }  }