#include <bits/stdc++.h>
using namespace std;

FILE *f = freopen( "divk.in", "r", stdin);
FILE *g = freopen( "divk.out", "w", stdout);

long long n, k, a, b, ans;
long long v[100005];
int vf[500005];

int main()
{
    int x;
    scanf( "%d%d%d%d", &n, &k, &a, &b );
    for( int i = 1; i <= n; ++i)
    {
        scanf( "%d", &x );
        v[i] = v[i - 1] + x;
        if( i - a >= 0 )
            ++vf[ v[i - a] % k ];
        if( i - b -1 >= 0 )
            --vf[ v[i - b - 1] % k];
        if( i - a >= 0)
            ans += vf[ v[i] % k ];
    }
    printf( "%d\n", ans );
    return 0;
}