Untitled

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

int main()
{
    int n,k,i,dem,sale=1;
    long long a[10000],b[10000];
    cin>>n>>k;
    for(i=1;i<=n;i++){
    	cin>>a[i]>>b[i];
    	k=k-b[i]-a[i];
    	if(k-b[i]-a[i]>0){
    		dem+=1;
		}
		if(a[i]%2!=0) 
			return 0;
	}
	if(k-b[i]-a[i]<0 and sale==1){
    		a[i]/=2;
    		if(k-b[i]-a[i]>=0)
    			dem+=1;
    		else if(k-b[i]-a[i]<0){
    			dem+=0;
			}
			sale--;
		}
    cout << dem;
}