#include <bits/stdc++.h>
#define ll long long
#define pii pair <int, int>
#define fi first
#define se second
#define pb push_back
#define int long long

using namespace std;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
const int N = 1e7+5, inf = 0x3f3f3f3f3f3f3f3f, mod = 998244353; 
int m, l, r, x, pr[N], n;   
string str; 

int sum (int n) { return n*(n+1)/2; }
int gets (int k, int c) {
	if (c == 0 && k) return inf; 
	if (c == 0) return 0; 
	return sum(k/c)*(c-k%c)+sum(k/c+1)*(k%c); 
}

void solve () {
	cin >> m >> l >> r >> x >> str; 
	n = m*x; 
	for (int i = 0;i < m;i++) {
		n += str[i]-'0'; 
		pr[i] = str[i] == '1' ? (i ? pr[i-1]+1 : 1) : 0; 
	}
	ll res = 1; 
	for (int i = 1;i <= m;i++) res = res*233%mod; 
	ll ans = sum(n); 
	for (int i = 1;i < m;i++) ans -= n-i+1; ans %= mod; 
	cout << ans*res%mod; 
}

signed main () {
//	ios::sync_with_stdio(0);
//	cin.tie(0); cout.tie(0);
	int T = 1; //cin >> T;
	while (T--) solve();
	return 0;
}
/*
3 0 3 3
101
*/