#include <bits/stdc++.h>
#define dim 1000009
using namespace std;
typedef long long ll;
ll n,m,a,b;
string s;
ll p[dim];
ll C[dim][3];
ll func(ll x, ll c)
{
    if (x > n) return 0;
    if (C[x][c] != 0) return C[x][c];

    if (c == 0)
    {
        if (x+a-1 > n) return 0;
        return C[x][c] = a + func(x+a,1);
    }
    else
    {
        if (x+b-1 > n) return 0;
        if (p[x+b-1] - p[x-1] < b) return 0;
        return C[x][c] = b + func(x+b,0);
    }
    return C[x][c];
}
int main()
{
    cin>>n;
    cin>>s;
    s = " " + s;
    cin>>m>>b>>a;
    ll res = 0;
    for (int i = 1; i <= n; i++)
    {
        p[i] = p[i-1];
        if (s[i] == '1') p[i]++;
    }
    ll nd = m*(a+b);
    for (int i = 1; i <= n-nd+1; i++)
    {
        res += (func(i,1) >= nd ? 1 :0);
    }
    cout<<res<<endl;
    return 0;
}