#include<iostream>
using namespace std;
typedef long long ll;
int n;
ll k;
const int N=110;
int a[N];
ll m=0,cnt=0;
int find(ll k)
{
    ll x=1;
    for(int i=1;;i++)
    {
        x=x*2;
        if(x>=k) 
        {
            m=x;
            return i;
        }
    }
}
int main()
{
    char x='a';
    cin>>k>>n;
    for(int i=0;i<n;i++) cin>>a[i];
    if(k==1)
    {
        cout<<"a";
        return 0;
    }
    while(k>1)
    {
        int x=find(k);
        if(k<=m/2) k=k%(m/2);
        else if(k>m/2)
        {
            if(a[x-1]==0) k=k-m/2;
            else if(a[x-1]==1) 
            {
                k=k-m/2;
                cnt++;
            }
        }
    }
    cnt%=26;
    char y=x+cnt;
    cout<<y;
    return 0;
}