#include<bits/stdc++.h>
using namespace std;
const int nax = 203;
const long long INF = 1e18;
const int P = 31;
const int M = 1e9 + 9;
int n;
string s;
long long A, B, C;
long long dp[nax][nax];
long long hv[nax];
long long pw[nax];
bool same(int l1, int r1, int l2, int r2) {
long long h1 = hv[r1] - hv[l1-1];
long long h2 = hv[r2] - hv[l2-1];
if(h1<0) h1 += M;
if(h2<0) h2 += M;
if(r1<r2) h1 = (h1 * pw[r2-r1]) % M;
else h2 = (h2 * pw[r1-r2]) % M;
return h1==h2;
}
long long solve(int i, int j) {
long long &ret = dp[i][j];
if(ret!=-1) return ret;
if(i==j) return A;
ret = min((j-i+1) * A, solve(i+1, j) + A);
for(int k=1; k<j-i+1; ++k) {
int cnt = 0;
int p = i;
while(p+k-1<=j) {
if(same(i, i+k-1, p, p+k-1)) {
++cnt;
p += k;
} else ++p;
}
long long cur = solve(i, i+k-1) + B;
cur += cnt * C;
cur += ((j-i+1) - cnt * k) * A;
ret = min(ret, cur);
}
return ret;
}
void PlayGround() {
cin>>n>>s>>A>>B>>C;
memset(dp, -1, sizeof dp);
s = '@' + s;
pw[0] = 1;
for(int i=1; i<=n; ++i) {
pw[i] = (pw[i-1] * P) % M;
hv[i] = (pw[i] * (s[i]-'a'+1)) + hv[i-1];
hv[i] %= M;
}
cout<<solve(1, n)<<'\n';
// cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
PlayGround();
return 0;
}
