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#include <bits/stdc++.h>

#define fs first
#define sc second
#define mp make_pair
#define eb emplace_back
#define sz(s) ((int) s.size())
#define all(s) s.begin(), s.end()

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef unsigned long long ull;

const ll linf = (ll) 1e18;

const int A = 26;
const int L = 17;
const int B = 315;
const int N = (int) 4e1;
const int inf = (int) 1e9 + 7;
const int mod = (int) 1e9 + 7;

const int di[] = {-1, +0, +1, +0};
const int dj[] = {+0, +1, +0, -1};

const ull P = 997;
const ull hmod = (ull) 1e9 + 7;

const double pi = acos(-1.0);
const double eps = 1e-11;

int h[N];
int g[N];

vector<long long> c[N >> 1];

inline void init() {

}
inline void solve() {
    int n; long long k; cin >> n >> k;
    for (int i = 0; i < n; i++) {
        cin >> h[i] >> g[i];
    }
    int x = n >> 1;
    long long ans = 0;
    for (int i = 1; i < (1 << x); i++) {
        bool f = 0;
        int last = 0;
        for (int j = 0; j < x; j++) {
            if ((i >> j) & 1) {
                if (h[j] < last) {
                    f = 1;
                    break;
                }
                last = h[j];
            }
        }
        if (!f) {
            last = -1;
            long long cur = 0;
            for (int j = 0; j < x; j++) {
                if ((i >> j) & 1) {
                    cur += g[j];
                    last = j;
                }
            }
            if (cur >= k) {
                ans++;
            }
            c[last].eb(cur);
        }
    }
    for (int i = 0; i < x; i++) {
        sort(all(c[i]));
    }
    /* upper part was first part, now goes second */
    reverse(h, h + n);
    reverse(g, g + n);
    int y = n - x;
    for (int i = 1; i < (1 << y); i++) {
        bool f = 0;
        int last = inf;
        for (int j = 0; j < y; j++) {
            if ((i >> j) & 1) {
                if (h[j] > last) {
                    f = 1;
                    break;
                }
                last = h[j];
            }
        }
        if (!f) {
            last = -1;
            long long cur = 0;
            for (int j = 0; j < y; j++) {
                if ((i >> j) & 1) {
                    cur += g[j];
                    last = j;
                }
            }
            if (cur >= k) {
                ans++;
            }
            for (int j = y; j < n; j++) {
                if (h[last] >= h[j]) {
                    int p = n - j - 1;
                    int pos = lower_bound(all(c[p]), k - cur) - c[p].begin();
                    ans += sz(c[p]) - pos;
                }
            }
        }
    }
    cout << ans;
}
int main() {
    #ifdef LOCAL
        #define name ""
        freopen(name".in", "r", stdin);
        freopen(name".out", "w", stdout);
    #endif
    int tests = 1;
    while (tests--) {
        init();
        solve();
    }
    return 0;
}