#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
#define pb emplace_back
#define all(n) (n).begin(),(n).end()
#define mem(n,x) memset(n,x,sizeof(n))
#define IOS ios::sync_with_stdio(0),cin.tie(0)
#define pii pair<ll,ll>
#define vi vector<ll>
#define dbg(...) cerr<<#__VA_ARGS__<<" = ";_do(__VA_ARGS__);
template<typename A> void _do(A x){ cerr<<x<<"\n"; }
template<typename A, typename ...B> void _do(A x, B ...y){ cerr<<x<<", "; _do(y...);}

ll x, y, base;

ll val(ll x,vi & v){
	ll ans = 0;
	for(auto &i:v){
		if( ans*1.0*x + i > 1e18 ) return 2e18;
		ans = ans * x + i;
	}
	return ans;
}

ll ok(vi &v){
	/* for(auto i:v) cout<<i<<" "; cout<<'\n'; */
	ll l = 1, r = 1e18;
	while(l < r){
		ll m = (l+r) / 2;
		if(val(m, v) >= x) r = m;
		else l = m + 1;
	}
	if(val(l, v) == x) return l;
	else return -1;
}

signed main(){
	IOS;
	cin>>x>>y;
	for(ll i=10;i*i*i<=x;i++){
		ll ans = 0, n = x, mul = 1;
		while(n){
			if(n % i >= 10) break;
			ans += n%i * mul;
			mul *= 10;
			n /= i;
			if(!n && ans >= y){
				base = i;
			}
		}
	}
	for(ll i=y;i<1000;i++){
		vector<ll> arr;
		ll x = i;
		while(x){
			arr.pb(x%10);
			x/=10;
		}
		reverse(all(arr));
		ll res = ok(arr);
		if(res != -1){
			base = max(base, res);
		}
	}
	cout<<base<<'\n';
}