#include<bits/stdc++.h>
using namespace std;
long long n,k,sum=1;
string a;
priority_queue <long long> q;
long long jiazh(long long x,long long y){
    for (long long i=x;i<=(x+y)/2;i++){
        if (a[i]!=a[x+y-i]){
            return 0;
        }
    }
    if ((y-x+1)%2==1) return 1;
    else return 0;
}
int main(){
    freopen("rehearse.in","r",stdin);
    freopen("rehearse.out","w",stdout);
    scanf("%lld%lld",&n,&k);
    cin>>a;
    if (n>1000) printf("-1");
    else{
        for (long long i=0;i<n;i++){
            for (long long j=i;j<n;j++){
                if (jiazh(i,j)==1){
                    q.push(j-i+1);
                }
            }
        }
        while (q.size()&&k){
            sum=sum*q.top()%19930726;
            q.pop();
            k--;
        }
        cout<<sum%19930726;
    }
    return 0;
}