diff --git a/core/src/main/java/com/hoc/flowmvi/core/EitherNes.kt b/core/src/main/java/com/hoc/flowmvi/core/EitherNes.kt
index 0f8af29c..e748b8b0 100644
--- a/core/src/main/java/com/hoc/flowmvi/core/EitherNes.kt
+++ b/core/src/main/java/com/hoc/flowmvi/core/EitherNes.kt
@@ -5,10 +5,6 @@ import arrow.core.NonEmptySet
 import arrow.core.left
 import arrow.core.nonEmptySetOf
 import arrow.core.right
-import arrow.core.toNonEmptySetOrNull
-import kotlin.contracts.ExperimentalContracts
-import kotlin.contracts.InvocationKind
-import kotlin.contracts.contract
 
 /**
  * A typealias for [Either] with [NonEmptySet] as the left side.
@@ -21,37 +17,16 @@ inline fun <A> A.rightNes(): EitherNes<Nothing, A> = this.right()
 @Suppress("NOTHING_TO_INLINE")
 inline fun <E> E.leftNes(): EitherNes<E, Nothing> = nonEmptySetOf(this).left()
 
-@OptIn(ExperimentalContracts::class)
 inline fun <E, A, B, C, Z> Either.Companion.zipOrAccumulateNonEmptySet(
   a: EitherNes<E, A>,
   b: EitherNes<E, B>,
   c: EitherNes<E, C>,
   transform: (A, B, C) -> Z,
-): EitherNes<E, Z> {
-  contract { callsInPlace(transform, InvocationKind.AT_MOST_ONCE) }
-
-  return if (
-    a is Either.Right &&
-    b is Either.Right &&
-    c is Either.Right
-  ) {
-    Either.Right(
-      transform(
-        a.value,
-        b.value,
-        c.value,
-      ),
-    )
-  } else {
-    Either.Left(
-      buildSet(capacity = a.count + b.count + c.count) {
-        if (a is Either.Left) this.addAll(a.value)
-        if (b is Either.Left) this.addAll(b.value)
-        if (c is Either.Left) this.addAll(c.value)
-      }.toNonEmptySetOrNull()!!,
-    )
-  }
-}
-
-@PublishedApi
-internal inline val <L, R> Either<L, R>.count: Int get() = if (isRight()) 1 else 0
+): EitherNes<E, Z> =
+  zipOrAccumulate(
+    combine = { acc, value -> acc + value },
+    a = a,
+    b = b,
+    c = c,
+    transform = transform,
+  )