#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
#include <cstring>
#include <iterator>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <fstream>
#include <iomanip>
#include <cassert>
//#include <utility>
//#include <memory>
//#include <functional>
//#include <deque>
//#include <cctype>
//#include <ctime>
//#include <numeric>
//#include <list>
//#include <iomanip>

//#if __cplusplus >= 201103L
//#include <array>
//#include <tuple>
//#include <initializer_list>
//#include <forward_list>
//
//#define cauto const auto&
//#else

//#endif

using namespace std;


typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll, vLL;
typedef vector<vector<long long> > vvll, vvLL;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
    v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
    stringstream ss;
    ss << f;
    ss >> t;
}

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define reep(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) reep((i),0,(n))
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define F first
#define S second
#define mkp make_pair
#define RALL(v) (v).rbegin(),(v).rend()
#define DEBUG
#ifdef DEBUG
#define dump(x)  cout << #x << " = " << (x) << endl;
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#else
#define dump(x) 
#define debug(x) 
#endif

#define MOD 1000000007LL
#define EPS 1e-8
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
#define maxs(x,y) x=max(x,y)
#define mins(x,y) x=min(x,y)

ll N, A;

ll powmod(ll xx,ll y){
	__int128 a=1;
	__int128 x=xx;
	while(y){
		if(y&1) a=a*x;
		x=x*x;
		mins(x, __int128(N+1));
		if(a>N){
			return N+1;
		}
		y>>=1;
	}
	return ll(a);
}

ll func(ll x){
	if(x<0) return INFL;
	if(x==0){
		return N;
	}
	ll t = pow((double)N, (double)1.0/(x+1));
	maxs(t, max(t-10,0LL));
	while(powmod(t, x+1)<N) t++;
	if(powmod(t, x+1)==N){
		return t*(x+1) + A*x;
	}
	t--;
	ll l = 0;
	ll r = x+1;
	while(r-l>1){
		// cout << l << " " << r << endl;
		ll mid = (r+l)/2;
		if(powmod(t+1,mid)*powmod(t,x+1-mid)>=N){
			r=mid;
		}
		else{
			l=mid;
		}
	}
	ll ret = (t+1)*r + t*(x+1-r);
	return ret + A*x;
}

void mainmain(){
	cin>>N>>A;
	if(N==1){
		cout << 1 << endl;
		return;
	}
	ll l = 0;
	ll r = 100000;
	// cout << func(1) << endl;
	// return;
	while(r-l>1000){
		ll mid1 = l+(r-l)/3;
		ll mid2 = l+(r-l)*2/3;
		ll val1 = INFL;
		ll val2 = INFL;
		val1 = func(mid1);
		val2 = func(mid2);
		// for(ll i = mid1-10;i < mid1+10;i++){
		// 	mins(val1, func(i));
		// }
		// for(ll i = mid2-10;i < mid2+10;i++){
		// 	mins(val2, func(i));
		// }
		if(val1 > val2){
			l = mid1;
		}
		else{
			r = mid2;
		}
	}
	ll ans = INFL;
	for(ll i = l-10; i < r+10; i++){
		mins(ans, func(i));
	}
	cout << ans << endl;
}


signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout<<fixed<<setprecision(20);
    mainmain();
}

Measured memory_bytes: 384