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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
#define _GLIBCXX_DEBUG
#define rep(i,n) for (int i = 0; i < (int)(n); i++)
#define all(v) v.begin(),v.end()
#define puts(i) cout << i << endl
#define INF INT_MAX;
#define INFL LLONG_MAX;
typedef long long ll;
using namespace std;

int main(){
  int R,G,B,n;
  cin >> R >> G >> B >> n;
  int64_t ans =0 ;
  for(int i=n/R;i>=0;i--){
    for(int j=(n-i*R)/G;j>=0;j--){
      if((n-R*i-G*j)%B==0) ans++;
    }
  }
  cout << ans << endl;
}