新版本第一题留念，棋盘动规
var
i,j,k,l,o,p,m,n:longint;
f:array[-100..1001,-100..1001] of longint;
a,b:array[0..1000,0..1000] of longint;
begin
f[0,0]:=1;
for i:=0 to 1000 do
for j:=0 to 1000 do
if ((i<>0) or (j<>0)) then f[i,j]:=(f[i-1,j]+f[i,j-1]+f[i+1,j]+f[i,j+1]) mod 1000000007;
while not eof do
begin
readln(n,m);
writeln(f[n-1,m-1]);
end;
end.