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#include<bits/stdc++.h>
using namespace std;
#define ll long long
inline int read(){
   int s=0,w=1;
   char ch=getchar();
   while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
   while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
   return s*w;
}
const int p=998244353,inf=1e9;
int n=read(),m=read();
struct node
{
	int fir[6];
	int tany[6];
	int tone[6][6];
	int nany[6][6];
	int none[6][6][6];
}f[1<<17];
node merge(node ls,node rs)
{
	node t=ls;
	for(int i=0; i<6; ++i)
		if(rs.fir[i]!=inf)
			for(int j=0; j<6; ++j)
				t.tone[j][i]=0;
	memset(t.nany,0,sizeof(t.nany));
	memset(t.none,0,sizeof(t.none));
	for(int i=0; i<6; ++i)
		for(int j=0; j<6; ++j)
		{
			if(rs.fir[j]==inf)
				t.nany[i][j]=(t.nany[i][j]
				+ls.nany[i][j])%p;
			else
			{
				t.tany[i]=(t.tany[i]+1ll*ls.nany[i][j]*rs.tany[j])%p;
				for(int k=0; k<6; ++k)
					t.nany[i][k]=(t.nany[i][k]+1ll*ls.nany[i][j]*rs.nany[j][k])%p;
			}
		}
	for(int i=0; i<6; ++i)
		for(int j=0; j<6; ++j)
		{
			int s=0;
			for(int k=0; k<6; ++k)
				if(rs.fir[j]==inf&&rs.fir[k]==inf)
					t.none[i][j][k]=(t.none[i][j][k]
					+ls.none[i][j][k])%p;
				else if(rs.fir[j]<=rs.fir[k])
					s=(s+ls.none[i][j][k])%p;
			for(int k=0; k<6; ++k)
				t.tone[i][k]=(t.tone[i][k]+1ll*s*rs.tone[j][k])%p;
			for(int k=0; k<6; ++k)
				for(int l=0; l<6; ++l)
					t.none[i][k][l]=(t.none[i][k][l]
					+1ll*s*rs.none[j][k][l])%p;
		}
	for(int i=0; i<6; ++i)
		if(rs.fir[i]!=inf&&ls.fir[i]==inf)
		{
			t.fir[i]=rs.fir[i],
			t.tany[i]=rs.tany[i],
			// memcpy(t.tany[i],rs.tany[i],sizeof(t.tany[i]));
			memcpy(t.tone[i],rs.tone[i],sizeof(t.tone[i]));
			memcpy(t.nany[i],rs.nany[i],sizeof(t.nany[i]));
			memcpy(t.none[i],rs.none[i],sizeof(t.none[i]));
		}
	return t;
}
char s[50003];
node init(int p)
{
	int v=s[p]-'a';
	node z=f[0];
	z.fir[v]=p,
	z.tany[v]=1,
	z.tone[v][v]=1;
	for(int i=0; i<6; ++i)
		z.nany[v][i]=1,
		z.none[v][i][v]=1;
	return z;
}
void build(int nl,int nr,int x)
{
	if(nl==nr){f[x]=init(nl);return ;}
	int mid=(nl+nr)>>1;
	build(nl,mid,x<<1),build(mid+1,nr,(x<<1)+1),
	f[x]=merge(f[x<<1],f[(x<<1)+1]);
	return ;
}
void update(int nl,int nr,int t,int x)
{
	if(nl==nr){f[x]=init(nl);return ;}
	int mid=(nl+nr)>>1;
	if(t<=mid) update(nl,mid,t,x<<1);
	else update(mid+1,nr,t,(x<<1)+1);
	f[x]=merge(f[x<<1],f[(x<<1)+1]);
	return ;
}
void solve()
{
	int ans=0;
	for(int i=0; i<6; ++i)
		ans=(ans+f[1].tany[i])%p;
	for(int i=0; i<6; ++i)
		for(int j=0; j<6; ++j)
			ans=(ans+p-f[1].tone[i][j])%p;
	printf("%d\n",ans);
}
signed main()
{
	for(int i=0; i<6; ++i) f[0].fir[i]=inf;
	scanf("%s",s+1),
	build(1,n,1),solve();
	for(int x; m--;)
		x=read(),s[x]=getchar(),
		update(1,n,x,1),solve();
	return 0;
}