#include <stdio.h>
int SP[500500], now[100100];
int main()
{int i, N, K, A, B;
freopen("divk.in", "r", stdin);
freopen("divk.out", "w", stdout);
scanf("%d%d%d%d", &N, &K, &A, &B);
for (i = 1; i <= N; i ++)
{int x;
scanf("%d", &x);
SP[i] = (SP[i - 1] + x) % K;
}
long long sol = 0;
for (i = A; i <= N; i ++)
{now[SP[i - A]] ++;
sol += now[SP[i]];
if (i >= B)
now[SP[i - B]] --;
}
printf("%lld", sol);
return 0;
}