UVA 10127 - Ones

 #include <iostream>
 #include <cstdio>
 #include <cmath>
 #include <cstring>
 #include <vector>
 #include <string>
 #include <sstream>
 #include <algorithm>
 #include <map>
 #include <bitset>
 #define MAX 1000000
 using namespace std;
 typedef long long int lli;
 
 int main(int argc, char *argv[]){
   int n;
   while (cin >> n){
     int digit=1, number=1;
     for (int number=1; number%n!=0; number=number*10+1, number%=n)
       digit++;
     cout << digit << endl ;
   }
   return 0;
 }