#include <bits/stdc++.h>
using namespace std;

int n;
long long const Mod=19930726;
long long k,res=1;
string s;

priority_queue< int,vector<int>,less<int> > q;

bool judge(int l,int r){
    if ((r-l)%2) return 0;
    int mid=(l+r)>>1;
    for (int i=l;i<mid;i++){
        if (s[i]!=s[l+r-i]) return 0;
    }
    return 1;
}

int main(){
    freopen("rehearse.in","r",stdin);
    freopen("rehearse.out","w",stdout);
    
    cin.tie(0);cout.tie(0);
    
    cin>>n>>k>>s;
    if (n>1000){
        printf("-1");
        return 0;
    }
    s=" "+s;
    for (int i=1;i<=n;i++){
        for (int j=1;j<=i;j++){
            if (judge(j,i)) q.push(i-j+1);
        }
    }
    long long w;
    for (int i=1;i<=k;i++){
        w=q.top();q.pop();
        res*=w;
        res%=Mod;
    }
    cout<<res%Mod;
    
    return 0;
}