#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include<stdio.h>
#include<iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<string.h>

#ifdef LOCAL
#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
#define NDEBUG
#define eprintf(...) do {} while (0)
#endif
#include<cassert>

using namespace std;

typedef long long LL;
typedef vector<int> VI;

#define REP(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
#define EACH(i,c) for(__typeof((c).begin()) i=(c).begin(),i##_end=(c).end();i!=i##_end;++i)

template<class T> inline void amin(T &x, const T &y) { if (y<x) x=y; }
template<class T> inline void amax(T &x, const T &y) { if (x<y) x=y; }
#define rprintf(fmt, begin, end) do { const auto end_rp = (end); auto it_rp = (begin); for (bool sp_rp=0; it_rp!=end_rp; ++it_rp) { if (sp_rp) putchar(' '); else sp_rp = true; printf(fmt, *it_rp); } putchar('\n'); } while(0)

int N, D, H;

void MAIN() {
    scanf("%d%d%d", &N, &D, &H);

    double ans = 0;
    REP (i, N) {
	int d, h;
	scanf("%d%d", &d, &h);

	double a = (double)(H-h) / (double)(D-d);
	double b = H - a * D;
	amax(ans, b);
    }
    printf("%.20f\n", ans);
}

int main() {
    int TC = 1;
//    scanf("%d", &TC);
    REP (tc, TC) MAIN();
    return 0;
}


#include <bits/stdc++.h> 

using namespace std; 

int main()
{
     
    int h, w, i, t, m = 101, e = 0 ; 
    vector<int> v; 
    cin >> h >> w ;
    for (i = 0; i < h*w; ++i) {  
        cin >> t; 
        v.push_back(t);  
        m = min(m, t);  
    } 
    for (i = 0; i < h*w; ++i)  
        e += v[i] > m ? v[i]-m : 0;   

    cout << e << endl;

}
