Problem:
Score : 200 points

Problem Statement

Snuke has come to a store that sells boxes containing balls. The store sells the following three kinds of boxes:

Red boxes, each containing R red balls

Green boxes, each containing G green balls

Blue boxes, each containing B blue balls

Snuke wants to get a total of exactly N balls by buying r red boxes, g green boxes and b blue boxes.
How many triples of non-negative integers (r,g,b) achieve this?

Constraints

All values in input are integers.

1 \leq R,G,B,N \leq 3000

Input

Input is given from Standard Input in the following format:

R G B N

Output

Print the answer.

Sample Input 1

1 2 3 4

Sample Output 1

4

Four triples achieve the objective, as follows:

(4,0,0)

(2,1,0)

(1,0,1)

(0,2,0)

Sample Input 2

13 1 4 3000

Sample Output 2

87058

Solution in Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

var sc = bufio.NewScanner(os.Stdin)

func nextLine() string {
	sc.Scan()
	return sc.Text()
}

func allAtoi(num []string) []int {
	conv := make([]int, len(num))
	for i, item := range num {
		conv[i], _ = strconv.Atoi(item)
	}
	return conv
}

func main() {
	RGBN := allAtoi(strings.Split(nextLine(), " "))
	R := RGBN[0]
	G := RGBN[1]
	B := RGBN[2]
	N := RGBN[3]
	// N = Rr + Gg + Bb
	ans := 0
	for r := 0; r <= N; r++ {
		Rr := R * r
		for g := 0; g <= N; g++ {
			Gg := G * g
			Bb := N - Rr - Gg
			if Bb >= 0 && Bb%B == 0 {
				ans++
			}
		}
	}
	fmt.Println(ans)
}