#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

int op(int a, int b){
    return a+b;
}

int e(){
    return 0;
}

int main()
{
    int n;
    string s;
    cin >> n >> s;
    int q;
    cin >> q;
    segtree<int, op, e> seg(n);
    vector<segtree<int, op, e>> cnt(26, seg);
    vector<segtree<int, op, e>> sum(26, seg);
    vector<set<int>> st(26);
    rep(i,n){
        cnt[s[i]-'A'].set(i,1);
        sum[s[i]-'A'].set(i,i);
        st[s[i]-'A'].insert(i);
    }
    rep(_,q){
        int t;
        cin >> t;
        if(t==1){
            int x;
            char c;
            cin >> x >> c;
            --x;
            st[s[x]-'A'].erase(x);
            cnt[s[x]-'A'].set(x,0);
            sum[s[x]-'A'].set(x,0);
            s[x] = c;
            cnt[s[x]-'A'].set(x,1);
            sum[s[x]-'A'].set(x,x);
            st[s[x]-'A'].insert(x);
        }else{
            int l, r;
            cin >> l >> r;
            --l;
            ll ans = 0;
            rep(i,26){
                ll c = cnt[i].prod(l, r);
                if(c<2) continue;
                auto it = st[i].lower_bound(l);
                ll s = sum[i].prod(l,r) - *it;
                ans += (c-1)*(r-1);
                ans -= s - (c-1)*(c-2)/2;
            }
            cout << ans << endl;
        }
    }
    return 0;
}