#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5+1;



void solve(){
    int n;
    cin>>n;
    string s;
    cin>>s;
    if(s[0] == s[n-1])
        cout<<n-1;
    else 
        cout<<n-2;
}

int main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    #ifndef ONLINE_JUDGE
        freopen("input.in", "r", stdin);
    #endif


    int tt=1;//cin>>tt;
    while(tt--)
        solve();
}