#include <bits/stdc++.h>
            #include<iostream>
            #include<cstdio>
            #include<vector>
            #include<queue>
            #include<map>
            #include<cstring>
            #include<string>
            #include <math.h>
            #include<algorithm>
        //    #include <boost/multiprecision/cpp_int.hpp>
            #include<functional>
          #define int long long
            #define inf  1000000007
            #define pa pair<int,int>
    #define ll long long
            #define pal pair<ll,ll>
            #define ppa pair<int,pa>
            #define  mp make_pair
            #define  pb push_back
            #define EPS (1e-10)
            #define equals(a,b) (fabs((a)-(b))<EPS)
     
            using namespace std;
     
            class Point{
            	public:
            	double x,y;
            	Point(double x=0,double y=0):x(x),y(y) {}
            	Point operator + (Point p) {return Point(x+p.x,y+p.y);}
            	Point operator - (Point p) {return Point(x-p.x,y-p.y);}
            	Point operator * (double a) {return Point(x*a,y*a);}
            	Point operator / (double a) {return Point(x/a,y/a);}
            	double absv() {return sqrt(norm());}
            	double norm() {return x*x+y*y;}
            	bool operator < (const Point &p) const{
            		return x != p.x ? x<p.x: y<p.y;
            	}
            	bool operator == (const Point &p) const{
            		return fabs(x-p.x)<EPS && fabs(y-p.y)<EPS;
            	}
            };
            typedef Point Vector;
     
            struct Segment{
            Point p1,p2;
            };
     
        double hen(Vector a){
        if(fabs(a.x)<EPS && a.y>0) return acos(0);
        else if(fabs(a.x)<EPS && a.y<0) return 3*acos(0);
        else if(fabs(a.y)<EPS && a.x<0) return 2*acos(0);
        else if(fabs(a.y)<EPS && a.x>0) return 0.0;
        else if(a.y>0) return acos(a.x/a.absv());
        else return 2*acos(0)+acos(-a.x/a.absv());
     
        }
     
int gcd(int v,int b){
	if(v>b) return gcd(b,v);
	if(v==b) return b;
	if(b%v==0) return v;
	return gcd(v,b%v);
}
            double dot(Vector a,Vector b){
            	return a.x*b.x+a.y*b.y;
            }
            double cross(Vector a,Vector b){
            	return a.x*b.y-a.y*b.x;
            }
        
            //----------------kokomade tenpure------------


int n,a,l;


bool power(int s){
	int z=1;
	for(int i=0;i<l;i++){
		z *= s;
		if(z >= n) return true;
	}
	return false;
	
}

int power1(int s){
	int z=1;
	for(int i=0;i<l;i++){
		z *= s;
//		if(z >= n) return true;
	}
	return z;
	
}
    signed main(){


    
    	cin>>n>>a;
    	
    	int ans=n;
 
    	
    	for( l=2;l<=1000;l++){
    		int sita=1,ue=100000000ll,med;
    	//	med=(sita+ue)/2;
    		while(ue-sita>1){
    				med=(sita+ue)/2;
    	//		cout<<med<<endl;
    			if( power(med) ){
    				ue=med;
    			}	
    			else sita=med;	
    		}
    	//	cout<<l<<" "<<ue<<endl;
    		int s=ue;
    		int e=power1(s);
    		int t=l*s+a*(l-1);
    	//	cout<<t<<" "<<e<<" "<<n<<endl;
    		while(e>= n){
    			e /= s;
    			e *= (s-1);
    			t--;
    			
    		}
    		t++;
    		e /= s-1;
    			e *= (s);
    	//	cout<<t<<endl;
    		ans=min(ans,t);
    		
    	//	cout<<endl;
    	}
    	
    	cout<<ans<<endl;
    	
    //	printf("%.10f\n",ans);
    	return 0;
    }

Measured memory_bytes: 384