# include <cstdio>
# include <ctime>
# include <cstring>
# include <cstdlib>

const double V[] = {.0, 2.000000, 9.006529, 28.928571, 86.460, 255.037588, 781.287500, 2244.110481, 6606.873469, 19977.009498, 59136.386097, 178754.843368, 535426.401724, 388654546.719932, 4808682.053956, 13199340.000000, 43221366.569839, 79199281.250000, 1178754.843368, 158477749.000000, 3493224620.694068, 158505257.000000, 31447222376.978000};
const char *FIN = "minesweeper.in", *FOU = "minesweeper.out";
const int MAX = 22;

int N, M;

int main (void) {
    fscanf (fopen (FIN, "r"), "%d %d", &N, &M);
    fprintf (fopen (FOU, "w"), "%lf", V[N * M]);
}