#include <bits/stdc++.h>

#define get_variable_name(x) #x
#define debug(x) cout << #x << " = " << x << endl

#define ALL(x) (x).begin(), (x).end()
#define SORT(x) sort((x).begin(), (x).end())
#define REVERSE(x) reverse( (x).begin(),(x).end())
#define UNIQUE(x) (x).erase(unique(ALL((x))), (x).end())
#define PW(x) (1LL<<(x))

using namespace std;
using ll = int64_t;
using P = pair<int, int>;

template<class T,class U>
ostream& operator<<(ostream &os, const pair<T, U> &p) {
    os << get_variable_name(p) << " = (" << p.first <<", " << p.second << ")";
    return os;
}

template<class T>
ostream& operator <<(ostream& os, const vector<T> &v){
    cout << get_variable_name(v) << " = [";
    for(auto i : v) 
        os << " " << v[i];
    os << " ]";
    return os;
}


const int INF = 1e8;

int f(double N, double K) {
    return 50 * N + floor(50*N/(0.8+0.2*K));
}

int main() {
    ios::sync_with_stdio(false);
    double A, B;
    cin >> A >> B;
    printf("%d\n", f(A, B));
}