SPLIT

#include <iostream>
#include <cstdio>
#define task "SPLIT"
using namespace std;
using ll = long long;
using ld = long double;

const int N = 1e3 + 2;
int m, n, k;
const int Inf = 1e9 + 7;
string s, p;
int dp[N][N][11];
int d[N][N][11];

void Read()
{
    cin >> m >> n >> k;
    cin >> s >> p;
    s = " " + s;
    p = " " + p;
}

void On3k()
{
    for (int i = 1; i <= m; ++i)
        for (int j = 1; j <= n; ++j)
        {
            if (s[i] == p[j])
            {
                for (int t = 1; t <= min(i, j); ++t)
                    if (s[i - t + 1] == p[j - t + 1])
                    {
                        for (int h = 1; h <= k; ++h)
                            if (dp[i - 1][j - 1][h - 1] > 0 || h == 1)
                                dp[i][j][h] = max(dp[i][j][h], dp[i - t][j - t][h - 1] + t);
                    }
                    else
                        break;
            }
            else
            {
                for (int h = 1; h <= k; ++h)
                    dp[i][j][h] = max(dp[i - 1][j][h], dp[i][j - 1][h]);
            }
        }
    cout << (dp[m][n][k] == 0 ? -1 : dp[m][n][k]);
}

void Solve()
{
    fill_n(&d[0][0][0], N * N * 11, -Inf);
    fill_n(&dp[0][0][0], N * N * 11, -1);
    for (int i = 1; i <= m; ++i)
        d[i][0][0] = -i;
    for (int i = 0; i <= n; ++i)
        d[0][i][0] = 0;
    for (int i = 1; i <= m; ++i)
        for (int j = 1; j <= n; ++j)
        {
            d[i][j][0] = -i;
            if (s[i] == p[j])
            {
                for (int t = k; t; --t)
                {
                    if (d[i - 1][j - 1][t - 1] == -Inf)
                        continue;
                    dp[i][j][t] = max(dp[i][j][t], d[i - 1][j - 1][t - 1] + i);
                    d[i][j][t] = max(d[i - 1][j - 1][t], dp[i][j][t] - i);
                }
                d[i][j][0] = d[i - 1][j - 1][0];
            }
            else
            {
                for (int h = 1; h <= k; ++h)
                {
                    dp[i][j][h] = max(dp[i - 1][j][h], dp[i][j - 1][h]);
                    if (dp[i][j][h] != 0)
                        d[i][j][h] = dp[i][j][h] - i;
                }
            }
        }
    cout << dp[m][n][k];
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
        freopen(task ".INP", "r", stdin),
            freopen(task ".OUT", "w", stdout);
    Read();
    Solve();
}