#include <bits/stdc++.h>   using namespace std;   int kor = 1e7;   int main() {     long long n, rad, v;     cin >> n >> rad >> v;     for (int i = 0; i < n; i++) {       int l, r;       cin >> l >> r;       long long d = r - l;       int ma = 0;       while (d < kor) {         d *= 10;         rad *= 10;         ma++;       }       long long mnv = 0;       long long mxv = d;       while (mnv != mxv) {         long long cv = (mnv + mxv) / 2;         double cd = cv + rad * sin((double)cv / rad);         if (cd < (d / 2)) {           mnv = cv + 1;           continue;         }         mxv = cv;       }       long long ev = mnv;       mnv = 0;       mxv = d;       while (mnv != mxv) {         long long cv = (mnv + mxv) / 2;         double cd = cv - rad * sin((double)cv / rad);         if (cd < (d / 2)) {           mnv = cv + 1;           continue;         }         mxv = cv;       }       long long bv = min(ev, mnv);       bv *= 2;       double t = (double)bv / v;       while (ma > 0) {         t /= 10;         rad /= 10;         ma--;       }       cout << setprecision(20) << t << endl;     }     cin >> n;   }   