Question

Hey, guys, I need some help figuring out what method should I use to solve it - for the life of me cannot figure this out!
There are two players who simultaneously select numbers from the closed interval, [-1, 1]. Suppose player 1 chooses s1 and player 2 chooses s2. If si < sj, then player i gets a payoff of (si +sj)/2 and the other player (j) gets 1 - (si + sj)/2, for i = 1, 2. If si = sj, both players get a payoff of 1⁄2. Find all pure-strategy Nash equilibria of this game.