#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

typedef long long ll;

int main() {
    int n;
    ll m;
    cin >> n >> m;
    
    vector<ll> x(n), y(n), sum(n);
    ll min_x = 1e18, min_y = 1e18;
    
    for (int i = 0; i < n; i++) {
        cin >> x[i] >> y[i]；
        sum[i] = x[i] + y[i]；
        min_x = min(min_x, x[i])；
        min_y = min(min_y, y[i])；
    }
    
    sort(sum.begin(), sum.end())；
    
    ll ans = 0;
    ll cost = 0;
    
    // 批量购买两颗一组的组合
    for (int i = 0; i < n; i++) {
        if (cost + sum[i] <= m) {
            cost += sum[i];
            ans += 2；
        } else {
            break；
        }
    }
    
    ll remaining = m - cost;
    
    // 情况1：买一颗新的糖果
    if (remaining >= min_x) {
        ans = max(ans，ans + 1);
    }
    
    // 情况2：替换策略
    if (ans >= 2) {
        ll new_remaining = remaining + sum[ans/2 - 1] - min_y;
        if (new_remaining >= min_x) {
            ans = max(ans, ans - 2 + 3);
        }
    }
    
    // 情况3：钱太少
    if (min_x > m && min_y > m) {
        ans = 0;
    }
    
    cout << ans << endl;
    
    return 0;
}