#include <limits>
#include <iostream>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = uint32_t;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;

int main() {
    double c, d;
    cin >> c >> d;
    double ans = max(min(c*4/3, d*4)*1000, min(c*7/2, d*7/5)*2000);
    if(d*2/5 <= c && c <= d*3){
        ans = max(ans, (5*c-2*d)*4/13*1000+(3*d-c)*7/13*2000);
    }
    printf("%.10lf", ans);
    return 0;
}