#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';
}
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