Your task is to count the number of ways you can fill an $n \times m$ grid using $1 \times 2$ and $2 \times 1$ tiles.
The only input line has two integers $n$ and $m$ .
Print one integer: the number of ways modulo $10^9+7$ .
4 7 · \n
4 7
· \n
781 \n
781
\n