diff --git a/algo/ucb.go b/algo/ucb.go
index d6a59bc..2bfe906 100644
--- a/algo/ucb.go
+++ b/algo/ucb.go
@@ -20,10 +20,10 @@ func (ucb *UCB) Select(r float64) int {
 	}
 	sz := len(ucb.cr.Counts)
 	var res float64
-	for _, v := range ucb.cr.Counts {
+	for idx, v := range ucb.cr.Counts {
 		ans := math.Sqrt((2.0 * math.Log(float64(sz))) / float64(v))
 		if ans > res {
-			res = ans
+			res = float64(a) + ucb.cr.Rewards[idx]
 		}
 	}
 	return int(res)