#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int MAXN = 2.5e3 + 5;

char s[MAXN];
int lcs[MAXN][MAXN], pre[MAXN][MAXN];
ll f[MAXN][MAXN];

int main(void) {
    int n;
    ll A, B, C;
    scanf("%d%s%lld%lld%lld", &n, s + 1, &A, &B, &C);

    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= n; ++j)
            lcs[i][j] = s[i] == s[j] ? lcs[i - 1][j - 1] + 1 : 0;

    for (int i = 1; i <= n; ++i) {
        static int mx[MAXN];
        memset(mx, 0, sizeof(mx));

        for (int j = i - 1; j >= 1; --j) {
            int k = min(i - j, lcs[i][j]);
            mx[k] = max(mx[k], j);
        }

        for (int j = i - 1; j >= 1; --j) {
            mx[j] = max(mx[j], mx[j + 1]);
            pre[i][j] = mx[j];
        }
    }

    memset(f, 0x3f, sizeof(f));

    for (int i = 1; i <= n; ++i)
        for (int j = i; j >= 1; --j) {
            f[i][j] = min({f[i][j], (ll)(i - j + 1) * A, f[i][j + 1] + A, f[i - 1][j] + A});

            int len = i - j + 1, pos = i;
            ll cur = f[i][j] + B;

            while (pos) {
                pos = pos - len + 1;
                cur += C;
                f[i][pos] = min(f[i][pos], cur);

                int nxt = pre[pos + len - 1][len];

                if (!nxt)
                    break;

                cur += (ll)A * (pos - nxt - 1);
                pos = nxt;
            }
        }

    printf("%lld", f[n][1]);
    return 0;
}