#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include "bits/stdc++.h" // define macro "/D__MAI"

using namespace std;
typedef long long int ll;

#define xprintf(fmt,...) fprintf(stderr,fmt,__VA_ARGS__)
#define debugv(v) {printf("L%d %s > ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debugm(m) {printf("L%d %s \n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}}
#define debuga(m,w) {printf("L%d %s > ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;}
#define debugaa(m,w,h) {printf("L%d %s >\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}}
#define debugaar(m,w,h) {printf("L%d %s >\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[y][x]<<" ";}cout<<endl;}}
#define ALL(v) (v).begin(),(v).end()
#define repeat(cnt,l) for(auto cnt=0;cnt<(l);++cnt)
#define iterate(cnt,b,e) for(auto cnt=(b);cnt!=(e);++cnt)
#define MD 1000000007ll
#define PI 3.1415926535897932384626433832795
template<typename T1, typename T2>
ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << "(" << p.first << ":" << p.second << ")"; return o; }

mt19937 mt(8901016);
inline int rand_int(int l, int h) {
    return uniform_int_distribution<>(l, h)(mt);
}

#ifdef __MAI
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
#ifdef __VSCC
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#endif
#ifdef __MAI
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
#ifdef __VSCC
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#endif
namespace {
#define isvisiblechar(c) (0x21<=(c)&&(c)<=0x7E)
    class MaiScanner {
    public:
        template<typename T> void input_integer(T& var) {
            var = 0;
            T sign = 1;
            int cc = getchar_unlocked();
            for (; cc<'0' || '9'<cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc&&cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var*sign;
        }
        inline int c() { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) {
            input_integer<int>(var);
            return *this;
        }
        inline MaiScanner& operator>>(long long& var) {
            input_integer<long long>(var);
            return *this;
        }
        inline MaiScanner& operator>>(string& var) {
            int cc = getchar_unlocked();
            for (; !isvisiblechar(cc); cc = getchar_unlocked());
            for (; isvisiblechar(cc); cc = getchar_unlocked())
                var.push_back(cc);
        }
        template<typename IT> void in(IT begin, IT end) {
            for (auto it = begin; it != end; ++it) *this >> *it;
        }
    };
}
MaiScanner scanner;


template<typename T>
//typedef int T;
class segtree {
    int size;
    vector<T> valdata;
    vector<int> addtree;
    vector<int> mintree;
    vector<int> maxtree;

    int _geti(const vector<int>& v, int idx) const {
        if (size - 1 <= idx) return (idx - size + 1);
        // if (idx < 0) return idx;
        return v[idx];
    }
public:

    segtree(int n) {
        size = 8;
        while (size < n) size <<= 1;
        mintree.resize(size);
        maxtree.resize(size);
        valdata.resize(size);
        addtree.resize(size);
    }

    // tree初期化
    void flat() {
        for (int i = size - 2; 0 <= i; --i) {
            int c = 2 * i + 1;
            if (size - 1 <= c) {
                mintree[i] = c - size + 1;
                maxtree[i] = c - size + 1;
            }
            else {
                mintree[i] = mintree[c];
                maxtree[i] = maxtree[c];
            }
        }
    }

    // TODO:verify
    // addtreeを0にして，valdataに加算する．
    void apply(T sum = 0, int ptr = 0) {
        if (size - 1 <= ptr) {
            valdata[ptr - size + 1] += sum;
        }
        else {
            sum += addtree[ptr];
            apply(sum, ptr * 2 + 1);
            apply(sum, ptr * 2 + 2);
            addtree[ptr] = 0;
        }
    }

    void fill(T val) {
        std::fill(valdata.begin(), valdata.end(), val);
        std::fill(addtree.begin(), addtree.end(), 0);
        flat();
    }

    // T operator[](int index) const {
    //     
    // }

    T getval(int index) const {
        T sum = valdata[index];
        index += size - 1;
        while (0 < index) {
            index = (index - 1) / 2; // 親へ移動
            sum += addtree[index];
        }
        return sum;
    }

    void setval(int index, const T e) {
        valdata[index] = e;

        for (int i = index + size - 1; 0 < i;) {
            i = (i - 1) / 2; // 親へ移動
            valdata[index] -= addtree[i];
        }
        index += size - 1;
        while (0 < index) {
            index = (index - 1) / 2; // 親へ移動
            int c1 = index * 2 + 1;
            int c2 = index * 2 + 2;
            int i1, i2;
            i1 = _geti(mintree, c1);
            i2 = _geti(mintree, c2);
            mintree[index] = getval(i1) < getval(i2) ? i1 : i2;
            i1 = _geti(maxtree, c1);
            i2 = _geti(maxtree, c2);
            maxtree[index] = getval(i1) > getval(i2) ? i1 : i2;
        }
    }

    void addvalrange(int begin, int end, const T e, int ptr = 0, int rangebegin = 0, int rangeend = 0) {
        if (rangeend <= rangebegin) { rangeend = size; }

        if (rangeend <= begin || end <= rangebegin) return;
        if (begin <= rangebegin && rangeend <= end) {
            if (size - 1 <= ptr)
                valdata[ptr - size + 1] += e;
            else
                addtree[ptr] += e;
            return;
        }

        int rangemid = (rangebegin + rangeend) / 2;
        addvalrange(begin, end, e, ptr * 2 + 1, rangebegin, rangemid);
        addvalrange(begin, end, e, ptr * 2 + 2, rangemid, rangeend);

        int i1, i2;
        i1 = _geti(mintree, ptr * 2 + 1);
        i2 = _geti(mintree, ptr * 2 + 2);
        mintree[ptr] = getval(i1) < getval(i2) ? i1 : i2;
        i1 = _geti(maxtree, ptr * 2 + 1);
        i2 = _geti(maxtree, ptr * 2 + 2);
        maxtree[ptr] = getval(i1) > getval(i2) ? i1 : i2;

    }

    int getminrangeIdx(int begin, int end, int ptr = 0, int rangebegin = 0, int rangeend = 0) const {
        if (rangeend <= rangebegin) { rangeend = size; }

        if (rangeend <= begin || end <= rangebegin) return begin; // note:範囲外なら適当な範囲内のindexを返す
        if (begin <= rangebegin && rangeend <= end) return _geti(mintree, ptr);

        int rangemid = (rangebegin + rangeend) / 2;
        int l = getminrangeIdx(begin, end, ptr * 2 + 1, rangebegin, rangemid);
        int r = getminrangeIdx(begin, end, ptr * 2 + 2, rangemid, rangeend);

        if (getval(l) <= getval(r))
            return l;
        else
            return r;
    }

    T getminrange(int begin, int end) {
        return getval(getminrangeIdx(begin, end));
    }

    int getmaxrangeIdx(int begin, int end, int ptr = 0, int rangebegin = 0, int rangeend = 0) const {
        if (rangeend <= rangebegin) { rangeend = size; }

        if (rangeend <= begin || end <= rangebegin) return begin; // note:範囲外なら適当な範囲内のindexを返す
        if (begin <= rangebegin && rangeend <= end) return _geti(maxtree, ptr);

        int rangemid = (rangebegin + rangeend) / 2;
        int l = getmaxrangeIdx(begin, end, ptr * 2 + 1, rangebegin, rangemid);
        int r = getmaxrangeIdx(begin, end, ptr * 2 + 2, rangemid, rangeend);

        if (getval(l) >= getval(r))
            return l;
        else
            return r;
    }

    T getmaxrange(int begin, int end) {
        return getval(getmaxrangeIdx(begin, end));
    }
};


int m, n, kei;
ll cc, vv;

//ll dp[200010];

int main() {

    scanner >> n >> cc >> vv;

    //fill(dp, dp + 200010, (ll)5e15);
    segtree<ll> dp(2*n+10);

    dp.fill(5e15);

    dp.setval(0, 0);
    dp.setval(1, 0);

    iterate(i, 1, n) {
        ll t = 1;
        ll nice = dp.getminrange(i, n+2);
        for (int j = i * 2; j <= n; j += i) {
            ll now = dp.getval(j);
            ll to = nice + cc + vv*t;

            if (to < now) {
                dp.setval(j, to);
            }
            ++t;
        }
        //debuga(dp,n+1)
    }

    ll best = 5e15;

    best = dp.getminrange(n, 2*n + 5);

    cout << best << endl;

    return 0;
}