#include<bits/stdc++.h>
using namespace std;
const int mod=1e9+7;
long long n,k,a[44],b[44],nm,tree[2500006],ans;
vector<pair<int,long long> >on,to;
vector<long long>vt,tk;
map<long long,int>mp;
void up(int nod,int l,int r,int x)
{
if(x<l||r<x)return;
if(l==r)
{
tree[nod]++;
return;
}
int mid=(l+r)/2;
up(nod*2,l,mid,x);
up(nod*2+1,mid+1,r,x);
tree[nod]=tree[nod*2]+tree[nod*2+1];
}
int qr(int nod,int l,int r,int x,int y)
{
if(x<=l&&r<=y)return tree[nod];
if(y<l||r<x)return 0;
int mid=(l+r)/2;
return qr(nod*2,l,mid,x,y)+qr(nod*2+1,mid+1,r,x,y);
}
void bt(int x,int mx,long long sum)
{
if(sum>=k)ans++;
if(sum>0)
{
if(mx==n/2)on.push_back({a[x],sum});
else
{
to.push_back({a[x],sum});
tk.push_back(sum);
}
vt.push_back(sum);
}
if(x==mx+1)return;
for(int i=x+1;i<=mx;i++)
{
if(a[x]<=a[i])bt(i,mx,sum+b[i]);
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
//freopen("gpsduel.in","r",stdin);
//freopen("gpsduel.out","w",stdout);
cin>>n>>k;
for(int i=1;i<=n;i++)cin>>a[i]>>b[i];
for(int i=1;i<=n;i++)bt(i,n,b[i]);
cout<<ans;
}
