#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr int INF = (int)1e9 + 1001010;
constexpr ll llINF = (ll)4e18 + 22000020;
const string endn = "\n";
template <class T> inline vector<vector<T>> vector2(size_t i, size_t j, const T &init = T()) {return vector<vector<T>>(i, vector<T>(j, init));}
const string ELEM_SEPARATION = " ", VEC_SEPARATION = endn;
template<class T> istream& operator >>(istream &i, vector<T> &A) {for(auto &I : A) {i >> I;} return i;}
template<class T> ostream& operator <<(ostream &o, const vector<T> &A) {int i=A.size(); for(auto &I : A){o << I << (--i ? ELEM_SEPARATION : "");} return o;}
template<class T> ostream& operator <<(ostream &o, const vector<vector<T>> &A) {int i=A.size(); for(auto &I : A){o << I << (--i ? VEC_SEPARATION : "");} return o;}
template<class T> vector<T>& operator ++(vector<T> &A, int n) {for(auto &I : A) {I++;} return A;}
template<class T> vector<T>& operator --(vector<T> &A, int n) {for(auto &I : A) {I--;} return A;}
template<class T, class U> bool chmax(T &a, const U &b) {return ((a < b) ? (a = b, true) : false);}
template<class T, class U> bool chmin(T &a, const U &b) {return ((a > b) ? (a = b, true) : false);}
ll floor(ll a, ll b) {assert(b != 0); return((a%b != 0 && ((a>0) != (b>0))) ? a/b-1 : a/b);}
ll ceil (ll a, ll b) {assert(b != 0); return((a%b != 0 && ((a>0) == (b>0))) ? a/b+1 : a/b);}
// ================================== ここまでテンプレ ==================================


int main(){
    ll w, z; cin >> w >> z;
    ll b;
    {
        int b1, b2; scanf("%d.%d", &b1, &b2);
        b = b1 * 10 + b2;
    }

    ll ans = (w+z) * b / 10 + (w+z);
    cout << ans << endl;
    return 0;
}