//https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 より
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

//

fn run() {
    input! {
        n: usize,
        k: usize,
        p: [(chars, u64); n],
    }
    let mut cnt = vec![vec![0; 3]; n];
    for i in 0..n {
        for (x, c) in cnt[i].iter_mut().zip("JOI".chars()) {
            *x = p[i].0.iter().filter(|p| **p == c).count();
        }
    }
    let mut target = vec![];
    for c in "JOI".chars() {
        for _ in 0..k {
            target.push(c);
        }
    }
    target.push('$');
    let mut dp = vec![std::u64::MAX / 2; 3 * k + 1];
    dp[0] = 0;
    for i in 0..(3 * k) {
        let val = dp[i];
        for j in 0..n {
            let cost = p[j].1;
            let c = cnt[j][i / k];
            if c + i <= i / k * k + k {
                dp[i + c] = std::cmp::min(dp[i + c], val + cost);
            }
            if i + p[j].0.len() > i / k * k + k {
                let mut next = i;
                for c in p[j].0.iter() {
                    if target[next] == *c {
                        next += 1;
                    }
                }
                dp[next] = std::cmp::min(dp[next], val + cost);
            }
        }
    }
    let ans = dp[3 * k];
    if ans > 1_000_000_000 * 3 * 100_000 {
        println!("-1");
    } else {
        println!("{}", ans);
    }
}

fn main() {
    run();
}