{ll @N,A=N+1,i=1,x;for(;i*i<=N;i++){if(N%i==0&&N/i-1>i)A<?=N/i-1;x=1;while(x*i<N)x=x*i+1;if(N%x==0&&N/x<i)(A<?=i);}wt(A);}