#include<bits/stdc++.h>
using namespace std;
const int mod=1e9+7;
long long n,k,a[44],b[44],nm,ans;
vector<pair<long long,long long> >on;
vector<long long>to[44];
vector<long long>cal;
map<long long,long long>mp;
void bt(int x,int y,int mx,long long sum)
{
if(y==mx+1)
{
if(sum>=k)ans++;
if(sum>0)
{
if(mx==n/2)on.push_back({mp[a[x]],sum});
else to[mp[a[x]]].push_back(sum);
}
return;
}
if(a[x]<=a[y])bt(y,y+1,mx,sum+b[y]);
bt(x,y+1,mx,sum);
}
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];
cal.push_back(a[i]);
}
sort(cal.begin(),cal.end());
for(int i=0;i<cal.size();i++)
{
if(mp[cal[i]]==0)mp[cal[i]]=++nm;
}
bt(0,1,n,0);
cout<<ans;
}
