// compile: make data
// run: ./data < data.in
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#ifdef LOCAL
#include <debug/codeforces.h>
#define debug(x...) _debug_print(#x, x);
#define Debug(x...) _debug_print_format(#x, x);
std::ifstream terminal("/dev/tty");
#define PP cerr<<"\033[1;30mpause...\e[0m",terminal.ignore();
#else
#define debug(x...)
#define Debug(x...)
#define PP
#endif
template<typename...Args> void print_(Args...args){((cout<<args<<" "),...)<<endl;}
#define VI vector<int>
#define VII vector<vector<int>>
#define VIII vector<vector<vector<int>>>
#define rep(i,a,b) for(int i=(a);i<(int)(b);++i)
#define sz(v) ((int)(v).size())
#define print(...) print_(__VA_ARGS__);
#define FIND(a, x) ((find(a.begin(),a.end(),(x))!=a.end())?1:0)
#define cmin(x,...) x=min({(x), __VA_ARGS__})
#define cmax(x,...) x=max({(x), __VA_ARGS__})
#define INTMAX (int)(9223372036854775807)
#define INF (int)(1152921504606846976)
#define NaN (int)(0x8b88e1d0595d51d1)
#define double long double
#define int long long
#define uint unsigned long long
#define MAXN 200010
#define P1 998244353
#define P2 1000000007

template <class T> struct segtree {
    struct node {
        int l, r;
        T val;
        node *ch[2];
    };
    int cnt = 0;
    T DEFAULT_VALUE;
    node *newnode(int l, int r) {
        node *x = (l==r) ? &datalist[l] : &datalist[cnt++];
        x->l = l, x->r = r;
        x->ch[0] = x->ch[1] = nullptr;
        x->val.size = r - l + 1;
        return x;
    }
    vector<int> a;
    vector<node> datalist;
    node *root;
    segtree(vector<int> arr) {
        cnt = sz(arr);
        a = arr, build();
    }
    void pushup(node *x) {
        if (!x) return;
        if (!x->ch[0] && !x->ch[1]) return;
        if (x->ch[0] && x->ch[1]) x->val = x->ch[0]->val + x->ch[1]->val;
        else x->val = x->ch[!x->ch[0]]->val;
    }
    T query(int ql, int qr) {
        if (qr - ql < 10) {
            T res = DEFAULT_VALUE;
            rep(i, ql, qr+1) res = res + datalist[i].val;
            return res;
        }
        function<T(node*)> dfs = [&](node *x) -> T {
            if (!x) return DEFAULT_VALUE;
            if (ql > x->r || qr < x->l) return DEFAULT_VALUE;
            if (x->l >= ql && x->r <= qr) return x->val;
            return dfs(x->ch[0]) + dfs(x->ch[1]);
        };
        return dfs(root);
    }
    template <typename U> void modify(int q, U val) {
        function<void(node*)> dfs = [&](node *x) -> void {
            if (q > x->r || q < x->l) return;
            if (x->l >= q && x->r <= q) {
                x->val.update(val);
                return;
            }
            dfs(x->ch[0]), dfs(x->ch[1]);
            pushup(x);
        };
        dfs(root);
    }
    void build() {
        datalist.resize(sz(a) * 2);
        function<node*(int, int)> dfs = [&](int l, int r) {
            node *x = newnode(l, r);
            if (r > l) x->ch[0] = dfs(l, (l+r) >> 1), x->ch[1] = dfs(((l+r)>>1) + 1, r);
            else x->val.set(a[l]);
            pushup(x);
            return x;
        };
        root = dfs(0, sz(a)-1);
    }
    void graphviz_dump(string filename = "graph.dot") {
        FILE *f = fopen(filename.c_str(), "w");
        fprintf(f, "digraph {\n");
        rep(i, 0, cnt) {
            node *x = &datalist[i];
            fprintf(f, "    %lld;\n");
        }
        rep(i, 0, cnt) {
            node *x = &datalist[i];
            if (x->ch[0]) fprintf(f, "    %lld -> %ld;\n", i, x->ch[0] - &datalist[0]);
            if (x->ch[1]) fprintf(f, "    %lld -> %ld;\n", i, x->ch[1] - &datalist[0]);
        }
        fprintf(f, "}\n");
    }
};

vector<int> pow1, pow2;

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

    struct value {
        int h1 = 0, h2 = 0;
        int size = 0;
        value operator+(const value &rhs) const {
            value lhs = *this;
            value res;
            res.h1 = (lhs.h1 * pow1[rhs.size] + rhs.h1) % P1;
            res.h2 = (lhs.h2 * pow2[rhs.size] + rhs.h2) % P2;
            res.size = lhs.size + rhs.size;
            return res;
        }
        void set(int rhs) {
            h1 = h2 = rhs;
        }
        void update(int val) {
            h1 = h2 = val;
        }
    };
    int n, q; cin >> n >> q;
    pow1.resize(n), pow2.resize(n);
    pow1[0] = pow2[0] = 1;
    rep(i, 1, n) pow1[i] = pow1[i-1] * 26 % P1, pow2[i] = pow2[i-1] * 26 % P2;

    vector<int> a(n), b(n);
    string s; cin >> s;
    rep(i, 0, s.length()) a[i] = s[i] - 'a', b[i] = s[n-i-1] - 'a';
    segtree<value> t(a), tinv(b);
    while (q--) {
        int op; cin >> op;
        if (op == 1) {
            int x; string c; cin >> x >> c; --x;
            t.modify(x, c[0] - 'a');
            tinv.modify(n-x-1, c[0] - 'a');
        }
        else {
            int l, r; cin >> l >> r; --l, --r;
            value hs = t.query(l, r);
            value hsinv = tinv.query(n-r-1, n-l-1);
            printf("%s\n", hs.h1 == hsinv.h1 && hs.h2 == hsinv.h2 ? "YES" : "NO");
        }
    }

    return 0;
}