#include <bits/stdc++.h> using namespace std; int main() { int n,sum; cin >> n; sum = n; while(1) { int temp = sum; sum = 1; while(temp) { if(temp%10!=0) { sum *= temp%10; } temp /= 10; } if(sum>=0&&sum<=9) { break; } } cout << sum; return 0; }