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++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;

int main() {
    ll r, g, b, n;
    cin >> r >> g >> b >> n;

    ll cnt=0;
    for(ll i=0; i<n+1; ++i) {
        if (i*r > n) break;
        for (ll j=0; j<n+1; ++j) {
            if (j*g > n || (i*r + j*g) > n) break;
            for (ll k=0; k<n+1; ++k) {
                if (k*g > n || (i*r + j*g + k*g) > n) break;
                if ((i*r + j*g + k*b) == n) {
                    cnt++;
                }
            }
        }
    }

    cout << cnt << endl;
    return 0;
}