#include <bits/stdc++.h>
int main() {
  long long int n, m, k, l, ans;
  scanf("%lld%lld%lld%lld", &n, &m, &k, &l);
  ans = (l + m - 1 + k) / m * m;
  if (k + l > n || ans > n)
    printf("-1");
  else
    printf("%lld", (k + l + m - 1) / m);
  return 0;
}
