#include<bits/stdc++.h>

using namespace std;

int main()
{
	int N;

    long long W;
    
    cin >> N >> W;
    
    vector<long long> v(N), w(N);

    for (int i = 0; i < N; ++i) {
    	cin >> v[i] >> w[i];
    }

    long long ans = 0;

    long long bestv = v[0], bestw = w[0];
    long long maxw = w[0];

    for (int i = 1; i < N; ++i) {
        if (bestv * w[i] < v[i] * bestw) {
            bestv = v[i];
            bestw = w[i];
        }
        if (maxw < w[i]) {
            maxw = w[i];
        }
    }

    long long least = (W - bestw * maxw + bestw) / bestw;

    vector<long long> dp(bestw * maxw, 0);
    
    for (int i = 1; i < bestw * maxw; ++i) {
        for (int j = 0; j < N; ++j) {
            if (w[j] <= i && dp[i] < dp[i - w[j]] + v[j]) {
                dp[i] = dp[i - w[j]] + v[j];
            }
        }
    }

    ans = least * bestv + dp[W - least * bestw];
    
    cout << ans << endl;
}