#include #include #include #include #include #include #include #include #include #define AS(a) (sizeof(a)/sizeof(a[0])) using namespace std; long long int MOD = 1000000007; long long int INF = 1000000007; int main() { int a,b; cin >> a >> b; cout << 50 * a + floor((250 * a) / (4 + b)) << endl; }