import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const N = readInt;
      const X = readLong;
      auto V = new long[N];
      auto W = new int[N];
      foreach (i; 0 .. N) {
        V[i] = readLong;
        W[i] = readInt;
      }
      
      const maxW = W.maxElement;
      const lim = maxW^^2;
      auto dp = new long[lim + 1];
      foreach (i; 0 .. N) {
        foreach (x; 0 .. lim - W[i] + 1) {
          chmax(dp[x + W[i]], dp[x] + V[i]);
        }
      }
      
      int im = 0;
      foreach (i; 0 .. N) {
        if (V[im] * W[i] < V[i] * W[im]) {
          im = i;
        }
      }
      long ans;
      if (X <= lim) {
        ans = dp[X];
      } else {
        const q = (X - lim + W[im] - 1) / W[im];
        ans = dp[X - q * W[im]] + q * V[im];
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}