#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <ctime>
#include <cassert>
using namespace std;

#ifdef LOCAL
    #define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
    #define eprintf(...) 42
#endif

typedef long long ll;
const int BASE = (int)1e9;
const int SZ = 16000 * 2;

/*
const int M = (int)4e8;
char buf[M];
int mpos = 0;

void* operator new (size_t n)
{
    mpos += n;
    assert(mpos < M);
    return buf + mpos - n;
}

void operator delete (void *) {}
*/

struct BigInt
{
    int a[SZ];
    int sz;
    BigInt () : a() {}
    BigInt (int x)
    {
        sz = 0;
        if (x == 0)
            a[sz++] = 0;
        while (x > 0)
        {
            a[sz++] = x % BASE;
            x /= BASE;
        }
    }
    BigInt operator + (const BigInt &b)
    {
        BigInt res = BigInt();
        int border = max(sz, b.sz);
        int z = 0;
        for (int i = 0; i < border || z; i++)
        {
            int value = (i < sz ? a[i] : 0) + (i < b.sz ? b.a[i] : 0) + z;
            res.a[res.sz++] = value % BASE;
            z = value / BASE;
        }
        return res;
    }
    BigInt operator - (const BigInt &b)
    {
        BigInt res = *this;
        int z = 0;
        for (int i = 0; i < sz; i++)
        {
            res.a[i] -= (i < b.sz ? b.a[i] : 0) + z;
            if (res.a[i] < 0)
            {
                res.a[i] += BASE;
                z = 1;
            }
            else
                z = 0;
        }
        while (res.sz > 1 && res.a[res.sz - 1] == 0)
            res.sz--;
        return res;
    }
    BigInt operator * (int b)
    {
        BigInt res = BigInt();
        int z = 0;
        for (int i = 0; i < sz || z; i++)
        {
            ll value = (i < sz ? a[i] : 0) * (ll)b + z;
            res.a[res.sz++] = value % BASE;
            z = value / BASE;
        }
        return res;
    }
    void shift(int x)
    {
        if (sz == 1 && a[0] == 0) return;
        while (x > 0)
        {
            sz++;
            for (int i = sz - 1; i > 0; i--)
                a[i] = a[i - 1];
            a[0] = 0;
            x--;
        }
    }
    bool operator < (const BigInt &b) const
    {
        if (sz != b.sz)
            return sz < b.sz;
        for (int i = (int)sz - 1; i >= 0; i--)
            if (a[i] != b.a[i])
                return a[i] < b.a[i];
        return false;
    }
    bool operator == (const BigInt &b) const
    {
        if (sz != b.sz)
            return false;
        for (int i = 0; i < (int)sz; i++)
            if (a[i] != b.a[i])
                return false;
        return true;
    }
    bool operator <= (const BigInt &b) const
    {
        if (sz != b.sz)
            return sz < b.sz;
        for (int i = (int)sz - 1; i >= 0; i--)
            if (a[i] != b.a[i])
                return a[i] < b.a[i];
        return true;
    }
    void print()
    {
        printf("%d", a[sz - 1]);
        for (int i = sz - 2; i >= 0; i--)
            printf("%09d", a[i]);
        puts("");
    }
};

bool check(BigInt &delta, BigInt &value, int x)
{
    BigInt A = BigInt(x);
    BigInt cur = value * 2 * x + A * x;
    eprintf("Check %d\n", x);
    return cur <= delta;
}

void printDigits(int d, int k)
{
    char value[12];
    sprintf(value, "%09d", d);
    for (int i = 0; i < min(k, 9); i++)
        printf("%c", value[i]);
}

int main()
{
    freopen ("input.txt", "r", stdin);
    freopen ("output.txt", "w", stdout);
    int n, k;
    scanf("%d%d", &n, &k);
    BigInt delta;
    BigInt value;
    for (int x = n; x >= 0; x--)
    {
        if (x * x <= n)
        {
            printf("%d.", x);
            delta = BigInt(n) - BigInt(x) * x;
            value = BigInt(x);
            break;
        }
    }
    while (k > 0)
    {
        delta.shift(2);
        value.shift(1);
        int l = 0, r = BASE;
        while (r - l > 1)
        {
            int m = (l + r) / 2;
            if (check(delta, value, m))
                l = m;
            else
                r = m;
        }
        eprintf("k = %d, value size = %d, delta size = %d\n", k, value.sz, delta.sz);
        return 0;
        printDigits(l, k);
        k -= 9;
        BigInt A = BigInt(l);
        delta = delta - (value * 2 * l + A * l);
        value = value + A;
    }

    return 0;
}