```go
package main

import "fmt"

func main() {
	var n int64
	fmt.Scan(&n)
	count := 0
	for h := int64(1); ; h++ {
		sum := n + h
		if sum % 3 != 0 {
			continue
		}
		S := sum / 3
		minS := h * (h + 1) / 2
		if S >= minS {
			count++
		}
		if minS*3 > n + h {
			break
		}
	}
	fmt.Println(count)
}
```