#include<bits/stdc++.h>
using namespace std;
#define il __int128
il get_log(long long x){
	il cnt=1;
	il res=0;
	while(cnt<x){
		cnt*=2;
		res++;
	}
	return res;
} 
il lgn,ans;
il qpow(il x,il y){
	int res=1;
	while(y){
		if(y&1) res*=x;
		x*=x;
		y>>=1;
	}
	return res;
}
int ans1[1010],len;
long long N,ax,ay;
il solve(il k){
	il res=ceil(powl(N,(long double)(1.0/k)));
	il l=1,r=res,t=res;
//	cout<<k<<" "<<l<<" "<<r<<" "<<res*k<<endl;
	il resl=(il)res*k;
	for(il p=1;p<=k;p++){
		l=1,r=res;
		while(l<=r){
			il mid=(l+r)>>1 ;
			if(qpow(mid,p)*qpow(mid+1,k-p)>N){
				r=mid-1;
				t=mid;
			}else{
				l=mid+1;
			}
		}
		resl=(resl<t*p+(t+1)*(k-p) ? resl : t*p+(t+1)*(k-p));
	}
	return resl;
}


signed main(){
	scanf("%lld%lld%lld",&N,&ax,&ay);
	lgn=get_log(N);
//	cout<<"N?log??"<<" "<<lgn<<endl;
//	cout<<endl; 
	for(il k=1;k<=lgn;k++){
	//	cout<<"??"<<k<<"?"<<endl; 
		if(k==1) {
			ans=((il)(ax-ay)*k+(il)ay*solve(k));
			continue;
		}
	//	cout<<"???Ai"<<" "<<solve(k)<<endl; 
	    ans=(ans>(il)(ax-ay)*k+(il)ay*solve(k) ? (il)(ax-ay)*k+(il)ay*solve(k) : ans);
	}
	while(ans){
		ans1[++len]=ans%10;
		ans/=10;
	}
	for(int i=len;i>=1;i--){
		printf("%d",ans1[i]);
	} 
	return 0; 
}