#include <bits/stdc++.h>
using namespace std;
const int INF = 2147483647;
const long long LLINF = 9223372036854775807LL;
int main() {
  int n, A, d;
  scanf("%d%d%d", &n, &A, &d);
  int KK = 0;
  double bst = 0;
  for (int i = 0; i < n; ++i) {
    int ti, vi;
    scanf("%d%d", &ti, &vi);
    double l = 0;
    double r = 1000010;
    double ps = vi / (A + .0);
    for (int it = 0; it < 100; ++it) {
      double m = 0.5 * (l + r);
      double curt = min(m, ps);
      double cur = A * curt * curt / 2.0;
      double rem = max(m - curt, .0);
      cur += rem * vi;
      if (cur < d)
        l = m;
      else
        r = m;
    }
    double cc = r + ti;
    if (cc < bst) cc = bst;
    printf("%.15lf\n", cc);
    bst = cc;
  }
  return 0;
}
