#include<bits/stdc++.h> using namespace std; int main(){ int s,n,ans=0; string s1,s2; cin>>n>>s; for(int i=1;i<=n;i++){ s=(s*345)%19997; s1=s1+(char)(97+(s%26)); } for(int i=1;i<=n;i++){ s=(s*345)%19997; s2=s2+(char)(97+(s%26)); } int a1=s1.length()-1,a2=s2.length()-1; for(int i=0;i<=a1;i++){ for(int j=0;j<=a2;j++){ if(s1[i]==s2[j]){ s1[i]='0'; s2[j]='0'; } } } for(int i=0;i<=a2;i++){ if(s2[i]!='0') ans++; } cout<<ans; return 0; }