#include using namespace std; #ifdef LOCAL #include "settings/debug.cpp" #else #define Debug(...) void(0) #endif #define rep(i, n) for (int i = 0; i < (n); ++i) using ll = long long; using ull = unsigned long long; int main() { int a, b; cin >> a >> b; cout << 50 * a + (500 * a / (8 + 2 * b)) << endl; return 0; }