# include<iostream> # include<cstring> using namespace std; int main(){ string a; cin>>a; int k; cin>>k; int len = a.size(); if(k==1){ cout<<a[0]; return 0; } int t=1; for(int i=0;i<len;i++){ if(a[i]==a[i]+1){ t++; if(t==k){ cout<<a[i]; return 0; } }else{ t=1; } } cout<<"NO"; return 0; }