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>
using namespace std;
#define rep(i,x,y) for (int i=x;i<=y;i++)
#define per(i,x,y) for (int i=x;i>=y;i--)
typedef long long ll;

inline int read()
{
    int x=0;
    char c=getchar();
    bool flag=0;
    while(c<'0'||c>'9')
	{
		if(c=='-') flag=1;
		c=getchar();
	}
    while(c>='0'&&c<='9')
	{
		x=(x<<3)+(x<<1)+c-'0';
		c=getchar();
	}
    return flag?-x:x;
}

int main()
{
	int red=read(),green=read(),blue=read(),n=read();
	ll ans;
	ans=0;
	int r,g;
	double b;
	rep(i,0,n/red)
	{
		rep(j,0,n/green)
		{
			r=i;
			g=j;
			b=((n-i*red-j*green)*1.0)/blue;
			if (b==int(b) && b>=0)
			{
				ans++;
				//cout<<i<<" "<<j<<endl;
			}
		}
	}
	cout<<ans<<endl;
	return 0;
}