#define NDEBUG
#ifdef NDEBUG
#define dbg(TXTMSG) if constexpr (false) cerr << "lol"
#define dbgv(VARN) ((void)0)
#define dbgfor(COND) if constexpr (false) for (COND)
#else
#define _GLIBCXX_DEBUG 1
#define _GLIBCXX_DEBUG_PEDANTIC 1
#pragma GCC optimize("trapv")
#define dbg(TXTMSG) cerr << "\n" << TXTMSG
#define dbgv(VARN) cerr << "\n" << #VARN << " = "<< VARN << ", line " << __LINE__ << "\n"
#define dbgfor(COND) for (COND)
#endif
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll,ll>;
#define e0 first
#define e1 second
constexpr ll INFTY = 2e18;
constexpr ll mod = 1e9+7;
ll powmod(ll b, ll e)
{
ll o = 1;
while (e>0)
{
if (e%2==1)
{
o*=b;
o%=mod;
}
b*=b;
b%=mod;
e/=2;
}
return o;
}
int main()
{
cin.tie(nullptr);
ios_base::sync_with_stdio(false);
dbgv("Started");
ll N,A,B,C;
string S;
cin >> N >> S >> A >> B >> C;
ll base = 31;
vector<ll> hashsum(N+1);
hashsum[0] = S[0]-'a'+1;
for (ll i = 0; i < N; ++i)
{
hashsum[i+1]=hashsum[i] + (S[i]-'a'+1)*powmod(base,i);
hashsum[i+1]%=mod;
}
auto gethash = [&](ll l, ll r)
{
return (((hashsum[r+1]-hashsum[l]+mod)%mod)*powmod(base,mod-1-l))%mod;
};
dbgv("hasdone");
vector<vector<ll>> nextcpy(N+1,vector<ll>());
for (ll l = 0; l <= N; ++l)
{
nextcpy[l].assign(N-l+1, INFTY);
map<ll,ll> seenhashidx;
for (ll i = N-2*l; i >= 0; --i)
{
seenhashidx[gethash(i+l,i+2*l-1)] = i+l;
auto it = seenhashidx.find(gethash(i,i+l-1));
if (it==seenhashidx.end())
{
nextcpy[l][i] = INFTY;
}
else
{
nextcpy[l][i] = it->e1;
}
}
}
//dbgv("ncpy done");
for (ll i = 0; i < N; ++i)
{
dbgv(gethash(i,i));
dbgv(nextcpy[1][i]);
}
vector<vector<ll>> cost(N+1, vector<ll>());
for (ll l = 1; l <= N; ++l)
{
cost[l].assign(N-l+1, INFTY);
}
cost[0].assign(N+1,0);
for (ll l = 1; l <= N; ++l)
{
for (ll i = 0; i <= N-l; ++i)
{
cost[l][i] = min({cost[l][i], cost[l-1][i]+A, A+cost[l-1][i+1]});
ll eidx = nextcpy[l][i];
dbgv(eidx);
ll npaste = 2;
while (eidx<INFTY)
{
cost[eidx-i+l][i] = min(cost[eidx-i+l][i], cost[l][i] + B + C*npaste + A*(eidx-i+l - l*npaste));
npaste++;
eidx = nextcpy[l][eidx];
}
}
}
for (ll i = 0; i < N-1; ++i)
{
//dbgv(gethash(i,i));
dbgv(cost[2][i]);
}
cout << cost[N][0];
}
