ABC311

n = int(input())
s = input()

A = B = C = False
for i in range(n):
    if s[i] == 'A': A = True
    if s[i] == 'B': B = True
    if s[i] == 'C': C = True
    if A and B and C: 
        exit(print(i+1))

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;

int main() {
    int n, d;
    cin >> n >> d;
    
    vector<string> s(n);
    rep(i, n) cin >> s[i];
    
    string t;
    rep(i, d) {
        bool ok = true;
        rep(j, n) if (s[j][i] == 'x') ok = false;
        if (ok) t += 'o'; else t += 'x';
    }
    
    int ans = 0, now = 0;
    rep(i, d) {
        if (t[i] == 'o') now++; else now = 0;
        ans = max(ans, now);
    }
    
    cout << ans << '\n';
    
    return 0;
}

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;

int main() {
    int n;
    cin >> n;
    
    vector<int> a(n+1);
    rep(i, n) cin >> a[i+1];
    
    vector<int> id(n+1);
    int k = 1;
    int v = 1;
    while (id[v] == 0) {
        id[v] = k; k++;
        v = a[v];
    }
    
    vector<int> ans;
    int len = k-id[v];
    rep(i, len) {
        ans.push_back(v);
        v = a[v];
    }
    
    cout << len << '\n';
    for (int v : ans) cout << v << ' ';
    
    return 0;
}