fn main() {
    let mut nvc = String::new();
    std::io::stdin().read_line(&mut nvc).ok();
    let nvc: Vec<usize> = nvc.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
    let n = nvc[0];
    let v = nvc[1];
    let c = nvc[2];
    let items = (0..n).map(|_| {
            let mut temp = String::new();
            std::io::stdin().read_line(&mut temp).ok();
            let temp: Vec<usize> = temp.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();
            (temp[0], temp[1])
        })
        .collect::<Vec<(usize, usize)>>();

    let mut dp = vec![vec![0usize; v+1]; n+1];
    for i in 0..n {
        let (val, w) = items[i];
        for j in 0..=v {
            dp[i+1][j] = dp[i+1][j].max(dp[i][j]);
            if j+val <= v {
                dp[i+1][j+val] = dp[i+1][j+val].max(dp[i][j] + c + w);
                dp[i+1][j+val] = dp[i+1][j+val].max(dp[i+1][j] + w);
            }
        }
    }
    println!("{}", dp[n][v]);
}