import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop;

void main() {
    auto s = readln.split.map!(to!int);
    auto N = s[0];
    auto M = s[1];
    auto A = iota(N).map!(_ => readln.split.map!(to!int).array).array;
    A.sort!"a[0] > b[0]";

    auto dp = new int[][][](N+1, M+1, 2);
    foreach (i; 0..N+1) foreach (j; 0..M+1) dp[i][j][1] = -(1 << 29);

    foreach (i; 0..N) foreach (j; 0..M+1) {
        int p = A[i][0];
        int d = A[i][1];
        dp[i+1][j][0] = max(dp[i+1][j][0], dp[i][j][0]);
        dp[i+1][j][1] = max(dp[i+1][j][1], dp[i][j][1]);
        if (p + j <= M) dp[i+1][j+p][1] = max(dp[i+1][j+p][1], dp[i][j][0] + d);
        dp[i+1][j][0] = max(dp[i+1][j][0], dp[i][j][1] + d);
    }

    int ans = 0;
    foreach (j; 0..M+1) foreach (k; 0..2) ans = max(ans, dp[N][j][k]);
    ans.writeln;
}