#include <bits/stdc++.h>

using namespace std;

long long comb(int n, int k) {
    if (k > n || k < 0) return 0;
    vector<long long> C(k + 1, 0);
    C[0] = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = min(i, k); j > 0; j--) {
            C[j] += C[j - 1];
        }
    }
    return C[k];
}

int main() {
    int a, b, c, k;
    cin >> a >> b >> c >> k;
    if (k > a + b + c) return cout << 0 , 0;
    cout << comb(a + b + c, k) - comb(b + c, k) - comb(a + c, k) - comb(a + b, k) + comb(c , k) + comb(b , k) + comb(a , k);
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

long long giaithua(int n) {
    if (n == 1) {
        return n;
    }
    return n * giaithua(n - 1);
}

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    int k;
    cin >> k;
    long long i = 0, j = 0, l = 0;

    if (a >= k) {
        i = (giaithua(a) / (giaithua(k) * giaithua(a - k)));
    } else if (b >= k) {
        j = (giaithua(b) / (giaithua(k) * giaithua(b - k)));
    } else if (c >= k) {
        l = (giaithua(c) / (giaithua(k) * giaithua(c - k)));
    }

    long long n = giaithua(a + b + c) / (giaithua(k) * giaithua(a + b + c - k));
    long long x = giaithua(a + b) / (giaithua(k) * giaithua(a + b - k));
    long long y = giaithua(b + c) / (giaithua(k) * giaithua(b + c - k));
    long long z = giaithua(a + c) / (giaithua(k) * giaithua(a + c - k));

    cout << n - (x + y + z + i + j + l) << endl;

    return 0;
}

def giaithua(n):
    if n==1:
        return n
    return n*giaithua(n-1)
a,b,c=map(int,input().split())
k=int(input())
i=j=l=0
if a>=k:
    i=(giaithua(a)//(giaithua(k)*giaithua(a-k)))
elif b>=k:
    j=(giaithua(b)//(giaithua(k)*giaithua(b-k)))
elif c>=k:
    l=(giaithua(c)//(giaithua(k)*giaithua(c-k)))
n=giaithua(a+b+c)//(giaithua(k)*giaithua(a+b+c-k))
x=(giaithua(a+b)//(giaithua(k)*giaithua(a+b-k)))
y=(giaithua(b+c)//(giaithua(k)*giaithua(b+c-k)))
z=(giaithua(a+c)//(giaithua(k)*giaithua(a+c-k)))
print(n-(x+y+z+i+j+l))