//演算除法时可以发现规律
//某个数不能被n整除时,余数乘以10+1是下一个数整除n时倒数第二位的余数
//以7为例
//         ___0_      ___1__       ___15_    ___158_     __1587_      ___15873__
//       7/    1    7/  11        /  111    /  1111     / 11111      /  111111
//       /-----       /----7---    /--- 7-   /----7---   /---7---     /  --7----
//            1            4            41        41         41            41
//                       ---35-    ---35--     --35--        --35---
//                       6    -----61-    ----61-       ----61--
//                                     56         56            56
//                                                    5          51          --51--
//                                         --49--     
//                                           -21-
//                                        ----21--
//                                             0 






#include <iostream>

using namespace std;

int main()
{
    int n;
    while(cin>>n)
    {
        if(n%5!=0)
        {    
            int j=1;
            int t=1;
            while(t%n)
            {
                t=t%n*10+1;
                j++;
            }
            cout<<j<<endl;
        }
    }
    return EXIT_SUCCESS;
}

评论