function nb=marguerite(c,i,j)
if rem(i,2) % lignes impaires
   nb=c(i,j)+c(i-1,j-1)+c(i-1,j)+c(i,j-1)+c(i,j+1)+c(i+1,j-1)+c(i+1,j);
else
   nb=c(i,j)+c(i-1,j)+c(i-1,j+1)+c(i,j-1)+c(i,j+1)+c(i+1,j)+c(i+1,j+1);
end
