#include <bits/stdc++.h>
#define rep(i,j,k) for(int i=(j);i<=(k);i++)
#define per(i,j,k) for(int i=(j);i>=(k);i--)
#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define db double
#define ldb long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define mkp make_pair
#define eb emplace_back
#define SZ(S) (int)S.size()
//#define mod 998244353
//#define mod 1000000007
#define inf 0x3f3f3f3f
#define linf 0x3f3f3f3f3f3f3f3f
using namespace std;

template <class T>
void chkmax(T &x,T y){
	if(x < y) x = y;
}

template <class T>
void chkmin(T &x,T y){
	if(x > y) x = y;
}

inline int popcnt(int x){
	return __builtin_popcount(x);
}

inline int ctz(int x){
	return __builtin_ctz(x);
}


/*ll power(ll p,int k = mod - 2){
	ll ans = 1;
	while(k){
		if(k % 2 == 1) ans = ans * p % mod;
		p = p * p % mod;
		k /= 2;	
	}
	return ans;
}*/
ll n,k;

#define eps 1e-7
int check(ldb V){
	ldb cur = 1;
	rep(i,1,k){
		cur = cur * V + 0.5;
		if(cur > 2e18) return 1;
		cur = (ll)cur;
		if(cur - n > -eps) return 1;
	}
	return 0;
}

int main(){
	scanf("%lld%lld",&n,&k);
	if(n == 1){
		printf("0.50000000\n");
		return 0;
	}
	ldb l = 1.5,r = n,mid;
	while(r > l * (1 + eps)){
		mid = (l + r) / 2;
		if(check(mid)) r = mid;
		else l = mid;
	}
	printf("%.10f\n",(db)l);
	return 0;
}