#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

using S = tuple<int, int,int, int, int>;
S op(S a, S b){
    auto [m, mm, ma, mma, len] = a;
    auto [m2, mm2, ma2, mma2,len2] = b;
    int m3 = m + m2;
    int mm3 = m * m2 + mm + mm2;
    int ma3 = ma + ma2 + m * (len2-m2);
    int mma3 = mma + mma2 + m*ma2 + mm * (len2-m2);
    return {m3,mm3,ma3,mma3,len+len2}; 
}

S e(){
    return {0,0,0,0,0};
}

int main()
{
    int n;
    string s;
    cin >> n >> s;
    int q;
    cin >> q;
    segtree<S, op, e> seg(n);
    vector<segtree<S, op, e>> cnt(26, seg);
    rep(i,n){
        rep(j,26){
            if(s[i]-'A'==j){
                cnt[j].set(i,{1,0,0,0,1});
            }
            else{
                cnt[j].set(i,{0,0,0,0,1});
            }
        }
    }
    rep(_,q){
        int t;
        cin >> t;
        if(t==1){
            int x;
            char c;
            cin >> x >> c;
            --x;
            rep(j,26){
                cnt[j].set(x,{0,0,0,0,1});
            }
            s[x] = c;
            rep(j,26){
                if(j==s[x]-'A'){
                    cnt[j].set(x,{1,0,0,0,1});
                }
                else{
                    cnt[j].set(x,{0,0,0,0,1});
                }
            }
        }else{
            int l, r;
            cin >> l >> r;
            --l;
            ll ans = 0;
            rep(i,26){
                S p = cnt[i].prod(l, r);
                auto [a,b,c,d, e] = p;
                ans += d;
            }
            cout << ans << endl;
        }
    }
    return 0;
}