Eric enjoys playing with numbers. One day, he writes $$$0,1,2,\dots,n$$$ on a piece of paper and decides to put $$$+$$$ and $$$-$$$ signs in between them to make the outcome equal to $$$x$$$. Can you help him finish his equation?
A single line that contains two integers $$$n,x$$$ $$$(1\le n\le 100,-\frac{n(n+1)}2\le x\le\frac{n(n+1)}2 )$$$.
If it's possible, output a single line of the final equation. Otherwise, output the string "IMPOSSIBLE" (without quotes).
3 6
0+1+2+3
4 9
IMPOSSIBLE
15 100
0+1+2+3+4+5+6+7+8+9-10+11+12+13+14+15