#include <bits/stdc++.h>
using namespace std;
long long a, b, ans2, ans5;
int main()
{
    cin >> a >> b;
    a--;
    long long aa = a, bb = b;
    while (aa != bb)
    {
        ans2++;
        aa /= 5, bb /= 5;
    }
    while (a != b)
    {
        ans5++;
        a /= 5, b /= 5;
    }
    cout << min(ans2, ans5) - 1;
    return 0;
}

为啥不对呀