{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;rep(j,2,i)x=1,while(x*j<N)x=x*j+1,if(N%x==0&&N/x<j)(A<?=j);wt(A);}