#include <iostream>
#include <iomanip>
#include <algorithm>
#include <bitset>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <cmath>
#include <time.h>
#include <random>
#include <string>
#include <cassert>
#include <vector>
#include <ostream>
#include <istream>
#include <stack>
#include <deque>
#include <queue>
#include <functional>
#include <chrono>
#include <stack>

using namespace std;

#define int long long
#define pb push_back
#define all(a) (a).begin(), (a).end()
#define pii pair<int, int>
#define ld long double

ostream& operator<< (ostream &out, const vector<int> &b) {
    for (auto k : b) out << k << " ";
    return out;
}

istream& operator>> (istream& in, pii& b) {
    in >> b.first >> b.second;
    return in;
}

ostream& operator<< (ostream& out, const pii& b) {
    out << "{" << b.first << ", " << b.second << "}";
    return out;
}

template <typename T1, typename T2> inline bool chkmin(T1 &x, const T2 &y) {if (x > y) {x = y; return 1;} return 0;}
template <typename T1, typename T2> inline bool chkmax(T1 &x, const T2 &y) {if (x < y) {x = y; return 1;} return 0;}


#ifdef LOCAL
    #define dbg(x) cout << #x << " : " << (x) << "\n";
    const int INF = 1e18;
    // const int mod = 2600000069;
    // const int p = 10;
#else
    #define dbg(x) 57
    const int INF = 1e18;
    // const int mod = 2600000069;
    // const int p = 179;
#endif

const ld PI = acos(-1);

#define time clock() / (double) CLOCKS_PER_SEC

// #pragma GCC optimize("Ofast,no-stack-protector")
// #pragma GCC target("sse,sse2,sse3,sse3,sse4")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC optimize("fast-math")
// #pragma GCC target("avx2")  
// #pragma GCC optimize("section-anchors")
// #pragma GCC optimize("profile-values,profile-reorder-functions,tracer")
// #pragma GCC optimize("vpt")
// #pragma GCC optimize("rename-registers")
// #pragma GCC optimize("move-loop-invariants")
// #pragma GCC optimize("unswitch-loops")
// #pragma GCC optimize("function-sections")
// #pragma GCC optimize("data-sections")

mt19937 gen(chrono::high_resolution_clock::now().time_since_epoch().count());

int mul(int a, int b) {
    if (INF / a < b) return INF;
    return a * b;
}

int binpow(int a, int p) {
    if (p == 0) return 1;
    if (p & 1) return mul(binpow(a, p - 1), a);
    int k = binpow(a, p / 2);
    return mul(k, k);
}

int sqrtk(int n, int k) {
    int l = 1, r = n + 1;
    while (r - l > 1) {
        int mid = (l + r) / 2;
        if (binpow(mid, k) > n) r = mid;
        else l = mid;
    }
    return l;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n, a;
    cin >> n >> a;
    int ans = n;
    for (int k = 1; k <= 43; k++) {
        // for (int c2 = 0; c2 <= 1; c2++) {
        //     for (int c3 = 0; c3 <= 4; c3++) {
        //         if (c2 + c3 > k) break;
        //         int c4 = k - c2 - c3;
        //         int x = 1;
        //         bool ok = 1;
        //         for (int i = 0; i < c2; i++) {
        //             ok &= mul(x, 2ll);
        //         }
        //         for (int i = 0; i < c3; i++) {
        //             ok &= mul(x, 3ll);
        //         }
        //         for (int i = 0; i < c4; i++) {
        //             ok &= mul(x, 4ll);
        //         }
        //         if (ok && x >= n) {
        //             chkmin(ans, (k - 1) * a + c2 * 2ll + c3 * 3ll + c4 * 4ll);
        //         }
        //     }
        // }
        int s = sqrtk(n, k);
        // cout << k << " " << s << "\n";
        for (int i = 0; i <= k; i++) {
            int x = binpow(s + 1, i);
            x = mul(x, binpow(s, k - i));
            if (x >= n) {
                chkmin(ans, (k - 1) * a + (s + 1) * i + s * (k - i));
            }
        }
    }
    cout << ans << "\n";
}
/*

*/


Measured memory_bytes: 3624