#include <fstream>
#define NMAX 500000

using namespace std;

ifstream fin ( "divk.in" );
ofstream fout ( "divk.out" );

long long  n, k, a, b, i, j, x[1 + NMAX], ans, nr;
long long  rest[1 + NMAX];

int main() {
    fin >> n >> k >> a >> b;
    for ( i = 1; i <= n; i++ ) {
        fin >> nr;
        x[i] = ( nr + x[i - 1] ) % k;
        if ( i >= a )
            rest[x[i - a]]++;
        if ( i - b >= 1 )
            rest[x[i - b - 1]]--;
        ans += rest[x[i]];
    }
    fout << ans;
}