#include <iostream>
using namespace std;
int N;
int K = 1;
int cnt = 1;
int main() {
cin >> N;
if(N % 2 ==0 || N%5==0) {
cout<<-1;
return 0;
}
if(N==1) {
cout << 1;
return 0;
}
while(true) {
K*=10;
K++;
cnt++;
if(K > N) K%=N;
if(K%N ==0) break;
}
cout<<cnt;
}