#include<bits/stdc++.h>
#define ri signed
#define pd(i) ++i
#define bq(i) --i
#define func(x) std::function<x>
namespace IO{
    char buf[1<<21],*p1=buf,*p2=buf;
    #define gc() p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?(-1):*p1++
    #define debug1(x) std::cerr << #x"=" << x << ' '
    #define debug2(x) std::cerr << #x"=" << x << std::endl
    #define Debug(x) assert(x)
    struct nanfeng_stream{
        template<typename T>inline nanfeng_stream &operator>>(T &x) {
            bool f=false;x=0;char ch=gc();
            while(!isdigit(ch)) f|=ch=='-',ch=gc();
            while(isdigit(ch)) x=(x<<1)+(x<<3)+(ch^48),ch=gc();
            return x=f?-x:x,*this;
        }
    }cin;
}
using IO::cin;
namespace nanfeng{
    #define FI FILE *IN
    #define FO FILE *OUT
    template<typename T>inline T cmax(T x,T y) {return x>y?x:y;}
    template<typename T>inline T cmin(T x,T y) {return x>y?y:x;}
    using ll=long long;
    static const int N=1e5+7,MOD=998244353;
    int n,m,opt,l,r,pos;
    char s[N],ch[3];
    struct Mat{
        int a,b;
        ll f[4][4];
        Mat(){memset(f,0,sizeof(f));}
        friend Mat operator*(const Mat &m1,const Mat &m2) {
            Mat res;
            for (ri i(0);i<=m1.a;pd(i)) 
                for (ri j(0);j<=m2.b;pd(j)) {
                    for (ri k(0);k<=m1.b;pd(k)) {
                        res.f[i][j]+=m1.f[i][k]*m2.f[k][j]%MOD;
                        // if (i==0&&j==3) printf("f[%d][%d]=%lld f[%d][%d]=%lld\n",i,k,m1.f[i][k],k,j,m2.f[k][j]);
                    }
                    res.f[i][j]%=MOD;
                }
            res.a=m1.a,res.b=m2.b;
            return res;
        } 
    }A,B,C,tmp,ad;
    struct Seg{
        #define ls(x) (x<<1)
        #define rs(x) (x<<1|1)
        #define up(x) T[x].sum=T[ls(x)].sum*T[rs(x)].sum
        struct segmenttree{Mat sum;}T[N<<2];
        func(void(int,int,int)) build=[&](int x,int l,int r) {
            if (l==r) {
                if (s[l]=='A') T[x].sum=A;
                else if (s[l]=='B') T[x].sum=B;
                else if (s[l]=='C') T[x].sum=C;
                return;
            }
            int mid=(l+r)>>1;
            build(ls(x),l,mid);
            build(rs(x),mid+1,r);
            up(x);
        };
        func(void(int,int,int,int)) update=[&](int x,int p,int l,int r) {
            if (l==r) {
                if (s[l]=='A') T[x].sum=A;
                else if (s[l]=='B') T[x].sum=B;
                else if (s[l]=='C') T[x].sum=C;
                return;
            }
            int mid=(l+r)>>1; 
            if (p<=mid) update(ls(x),p,l,mid);
            else update(rs(x),p,mid+1,r);
            up(x);
        };
        func(Mat(int,int,int,int,int)) query=[&](int x,int l,int r,int lt,int rt) {
            if (l<=lt&&rt<=r) return T[x].sum;
            int mid=(lt+rt)>>1;
            Mat res=tmp;
            if (l<=mid) res=res*query(ls(x),l,r,lt,mid);
            if (r>mid) res=res*query(rs(x),l,r,mid+1,rt);
            return res;
        };
    }T;
    inline int main() {
        FI=freopen("string.in","r",stdin);
        FO=freopen("string.out","w",stdout);
        scanf("%d%d%s",&n,&m,s+1);
        A.f[0][0]=B.f[0][0]=C.f[0][0]=1;
        A.f[0][1]=B.f[0][2]=C.f[0][3]=1;
        A.f[1][1]=A.f[2][1]=A.f[3][1]=A.f[2][2]=A.f[3][3]=1;
        B.f[1][1]=B.f[1][2]=B.f[3][2]=B.f[2][2]=B.f[3][3]=1;
        C.f[1][1]=C.f[1][3]=C.f[2][3]=C.f[2][2]=C.f[3][3]=1;
        tmp.f[0][0]=tmp.f[1][1]=tmp.f[2][2]=tmp.f[3][3]=1;
        ad.f[0][0]=1;
        A.a=A.b=B.a=B.b=C.a=C.b=tmp.a=tmp.b=3;
        ad.a=0,ad.b=3;
        T.build(1,1,n);
        for (ri i(1);i<=m;pd(i)) {
            scanf("%d",&opt);
            if (opt==1) {
                scanf("%d%s",&pos,ch+1);
                if (s[pos]!=ch[1]) {
                    s[pos]=ch[1];
                    T.update(1,pos,1,n);
                }
            } else {
                scanf("%d%d",&l,&r);
                Mat ans=T.query(1,l,r,1,n);
                printf("%lld\n",(ans.f[0][1]+ans.f[0][2]+ans.f[0][3])%MOD);
            }
        }
        return 0;
    }
}
int main() {return nanfeng::main();}