//----------vahagng----------//
#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
using namespace std;
// using namespace __gnu_pbds;
// template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
void print(long long t) { cerr << t; }
void print(int t) { cerr << t; }
void print(string t) { cerr << t; }
void print(char t) { cerr << t; }
void print(double t) { cerr << t; }
void print(long double t) { cerr << t; }
void print(unsigned long long t) { cerr << t; }
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[], V n) { cerr << "["; for (int i = 0; i < n; i++) { cerr << v[i] << " "; } cerr << "]"; }
template <class T, class V> void print(pair <T, V> p) { cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}"; }
template <class T> void print(vector <T> v) { cerr << "[ "; for (T i : v) { print(i); cerr << " "; } cerr << "]"; }
template <class T> void print(set <T> v) { cerr << "[ "; for (T i : v) { print(i); cerr << " "; } cerr << "]"; }
template <class T> void print(multiset <T> v) { cerr << "[ "; for (T i : v) { print(i); cerr << " "; } cerr << "]"; }
template <class T, class V> void print(map <T, V> v) { cerr << "[ "; for (auto i : v) { print(i); cerr << " "; } cerr << "]"; }
#define ll long long
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define ld long double
#define sz(v) v.size()
#define endl '\n'
const ll inf = 2e18, mod = 1e9 + 7, mod2 = 998244353;
void SetIO(string str = "") {
    if (str != "") {
        freopen((str + ".in").c_str(), "r", stdin);
        freopen((str + ".out").c_str(), "w", stdout);
    }
    else {
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    }
}
void FastIO() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
}
const int N = 2e5 + 10, M = 1e7 + 10;
mt19937 rnd(chrono::system_clock::now().time_since_epoch().count());
ll binpow(ll a, ll b, ll m) {
    ll res = 1;
    while (b) {
        if (b & 1) {
            res = (res * a) % m;
        }
        b >>= 1;
        a = (a * a) % m;
    }
    return res;
}
ll n, m, dp[303][303];
string s, t;
ll rec(int i, int j){
    if(j == m+1) return 0;
    if(dp[i][j] != -1) return dp[i][j];
    ll res = inf;
    for(int it = 1; it <= n; it++){
        if(s[it] == s[i]){
            for(int jj : {-1, 1}){
                if(it + jj < 1 || it + jj > n) continue;
                if(s[it+jj] != t[j]) continue;
                res = min(res, rec(it + jj, j + 1) + abs(it - i) + 1);
            }
        }
    }
    return dp[i][j] = res;
}
void solve(int tc) {
    cin >> n >> m >> s >> t;
    s = "$" + s;
    t = "$" + t;
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++){
            dp[i][j] = -1;
        }
    }
    ll ans = inf;
    for(int i = 1; i <= n; i++){
        if(s[i] == t[1]){
            dp[i][1] = 0;
            ans = min(ans, rec(i, 2));
        }
    }
    if(ans == inf) ans = -1;
    cout << ans << endl; 
}
void precalc() {
}
int main() {
    // SetIO("teamwork");
    FastIO();
    int test_case = 1;
    // cin >> test_case;
    precalc();
    int cnt = 1;
    while (test_case--) {
        solve(cnt++);
    }
    return 0;
}
Compilation message (stderr)
bajka.cpp: In function 'void SetIO(std::string)':
bajka.cpp:47:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |         freopen((str + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bajka.cpp:48:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |         freopen((str + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bajka.cpp:51:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
bajka.cpp:52:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~| # | Verdict | Execution time | Memory | Grader output | 
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