ll@n,@k,@l,@p;
ll n1=n>>1,n2=n-n1;
vector<pair<ll,ll>>g1[18],g2[18];

// hanbun zen rekkyo
g1[0].push_back({0,0});
rep(i,n1){
	ll@a,@b;
	rrep(j,i+1){
		for(auto x:g1[j]){
			g1[j+1].push_back({x.first+b,x.second+a});
		}
	}
}
g2[0].push_back({0,0});
rep(i,n2){
	ll@a,@b;
	rrep(j,i+1){
		for(auto x:g2[j]){
			g2[j+1].push_back({x.first+b,x.second+a});
		}
	}
}

// zaatsu cost
ll za[1<<18],zn=0;
rep(i,n1+1){
	for(auto x:g1[i]){
		za[zn++]=l-x.second;
	}
}
rep(i,n2+1){
	for(auto x:g2[i]){
		za[zn++]=x.second;
	}
}
coordcomp(zn,za);
zn=0;
rep(i,n1+1){
	for(auto&x:g1[i]){
		x.second=za[zn++];
	}
}
rep(i,n2+1){
	for(auto&x:g2[i]){
		x.second=za[zn++];
	}
}

// kazoeru
ll z=0;
ll j=0;
vector<pair<ll,ll>>g;
rrep(i,n1+1){
	while(j<=n2&&i+j<=k){
		g.insert(g.end(),g2[j].begin(),g2[j].end());
		++j;
	}
	sort(g.begin(),g.end());
	sort(g1[i].begin(),g1[i].end());
	ll l=g.size()-1;
	fenwick<ll>f;
	f.malloc(1<<18,1);
	for(auto x:g1[i]){
		while(l>=0&&x.first+g[l].first>=p){
			f.add(g[l].second,1);
			--l;
		}
		z+=f.get(x.second);
	}
}
wt(z);