# include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
const double pi = acos(-1);
template<class T>constexpr T inf() { return ::std::numeric_limits<T>::max(); }
template<class T>constexpr T hinf() { return inf<T>() / 2; }
template <typename T_char>T_char TL(T_char cX) { return tolower(cX); }
template <typename T_char>T_char TU(T_char cX) { return toupper(cX); }
template<class T> bool chmin(T& a,T b) { if(a > b){a = b; return true;} return false; }
template<class T> bool chmax(T& a,T b) { if(a < b){a = b; return true;} return false; }
int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; }
int d_sum(ll n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; }
int d_cnt(ll n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; }
ll gcd(ll a, ll b) { if (b == 0)return a; return gcd(b, a%b); };
ll lcm(ll a, ll b) { ll g = gcd(a, b); return a / g*b; };
ll MOD(ll x, ll m){return (x%m+m)%m; }
ll FLOOR(ll x, ll m) {ll r = (x%m+m)%m; return (x-r)/m; }
template<class T> using dijk = priority_queue<T, vector<T>, greater<T>>;
# define all(qpqpq)           (qpqpq).begin(),(qpqpq).end()
# define UNIQUE(wpwpw)        (wpwpw).erase(unique(all((wpwpw))),(wpwpw).end())
# define LOWER(epepe)         transform(all((epepe)),(epepe).begin(),TL<char>)
# define UPPER(rprpr)         transform(all((rprpr)),(rprpr).begin(),TU<char>)
# define rep(i,upupu)         for(ll i = 0, i##_len = (upupu);(i) < (i##_len);(i)++)
# define reps(i,opopo)        for(ll i = 1, i##_len = (opopo);(i) <= (i##_len);(i)++)
# define len(x)                ((ll)(x).size())
# define bit(n)               (1LL << (n))
# define pb push_back
# define eb emplace_back
# define exists(c, e)         ((c).find(e) != (c).end())

struct INIT{
	INIT(){
		std::ios::sync_with_stdio(false);
		std::cin.tie(0);
		cout << fixed << setprecision(20);
	}
}INIT;

namespace mmrz {
	void solve();
}

int main(){
	mmrz::solve();
}
#define debug(...) (static_cast<void>(0))

using namespace mmrz;


template <std::uint_fast64_t Modulus> class modint {
	using u64 = std::uint_fast64_t;
public:
	u64 a;
	constexpr modint(const u64 x = 0) noexcept : a(x % Modulus) {}
	constexpr u64 &value() noexcept { return a; }
	constexpr const u64 &value() const noexcept { return a; }
	constexpr modint operator+(const modint rhs) const noexcept {
		return modint(*this) += rhs;
	}
	constexpr modint operator-(const modint rhs) const noexcept {
		return modint(*this) -= rhs;
	}
	constexpr modint operator*(const modint rhs) const noexcept {
		return modint(*this) *= rhs;
	}
	constexpr modint operator/(const modint rhs) const noexcept {
		return modint(*this) /= rhs;
	}
	constexpr modint &operator+=(const modint rhs) noexcept {
		a += rhs.a;
		if (a >= Modulus) {
			a -= Modulus;
		}
		return *this;
	}
	constexpr modint &operator-=(const modint rhs) noexcept {
		if (a < rhs.a) {
			a += Modulus;
		}
		a -= rhs.a;
		return *this;
	}
	constexpr modint &operator*=(const modint rhs) noexcept {
		a = a * rhs.a % Modulus;
		return *this;
	}
	constexpr modint &operator/=(modint rhs) noexcept {
		u64 exp = Modulus - 2;
		while (exp) {
			if (exp % 2) {
				*this *= rhs;
			}
			rhs *= rhs;
			exp /= 2;
		}
		return *this;
	}

	friend std::ostream& operator<<(std::ostream& os, const modint& rhs) {
		os << rhs.a;
		return os;
	}
};
using mint = modint<998244353>;


template<typename mint>
mint power(mint n, long long k) {
	mint ret = 1;
	while(k > 0) {
		if(k & 1)ret *= n;
		n = n*n;
		k >>= 1;
	}
	return ret;
}

long long power(long long n, long long k, long long p) {
	long long ret = 1;
	while(k > 0){
		if(k & 1)ret = ret*n % p;
		n = n*n % p;
		k >>= 1;
	}
	return ret;
}

void SOLVE(){
	int n, m;
	cin >> n >> m;
	string s;
	cin >> s;
	vector<vector<int>> g(n);
	while(m--){
		int a, b;
		cin >> a >> b;
		a--, b--;
		g[a].pb(b);
		g[b].pb(a);
	}

	int cq = 0;
	rep(i, n)if(s[i] == '?')cq++;
	debug(cq);

	mint ans = 0;

	rep(i, n){
		if(len(g[i]) < 2)continue;
		rep(j, len(g[i]))rep(k, len(g[i]))if(j != k){
			bool flg = true;
			int cnt = 0;
			if(s[g[i][j]] == '?')cnt++;
			else if(s[g[i][j]] != 'a')flg = false;
			if(s[i] == '?')cnt++;
			else if(s[i] != 'o')flg = false;
			if(s[g[i][k]] == '?')cnt++;
			else if(s[g[i][k]] != 'i')flg = false;
			if(not flg)continue;
			ans += power(26, cq-cnt);
		}
	}
	cout << ans << '\n';
}

void mmrz::solve(){
	int t = 1;
	//cin >> t;
	while(t--)SOLVE();
}