#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define io ios::sync_with_stdio(false); cin.tie(0)

int main()
{
    io;
    int a, b;
    cin >> a >> b;
    double res = 100*((double)a-b)/a;
    cout << setprecision(5) << res << endl;
    return 0;
}
#include <bitset>
#include <deque>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#include <algorithm>
#include <functional>
#include <iterator>
#include <locale>
#include <memory>
#include <stdexcept>
#include <utility>
#include <string>
#include <fstream>
#include <ios>
#include <iostream>
#include <iosfwd>
#include <iomanip>
#include <istream>
#include <ostream>
#include <sstream>
#include <streambuf>
#include <complex>
#include <numeric>
#include <valarray>
#include <exception>
#include <limits>
#include <new>
#include <typeinfo>
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <climits>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdlib>
#include <cstddef>
#include <cstdarg>
#include <ctime>
#include <cstdio>
#include <cstring>
#include <cwchar>
#include <cwctype>
using namespace std;
static const double EPS = 1e-8;
static const double PI = 4.0 * atan(1.0);
static const double PI2 = 8.0 * atan(1.0);
using ll = long long;
using ull = unsigned long long;

#define ALL(c) (c).begin(), (c).end()
#define CLEAR(v) memset(v,0,sizeof(v))
#define MP(a,b) make_pair((a),(b))
#define REP(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
#define ABS(a) ((a)>0?(a):-(a))
template<class T> T MIN(const T& a, const T& b) { return a < b ? a : b; }
template<class T> T MAX(const T& a, const T& b) { return a > b ? a : b; }
template<class T> void MIN_UPDATE(T& a, const T& b) { if (a > b) a = b; }
template<class T> void MAX_UPDATE(T& a, const T& b) { if (a < b) a = b; }

constexpr int mo = 1000000007;
int qp(int a,ll b){int ans=1;do{if(b&1)ans=1ll*ans*a%mo;a=1ll*a*a%mo;}while(b>>=1);return ans;}
int qp(int a,ll b,int mo){int ans=1;do{if(b&1)ans=1ll*ans*a%mo;a=1ll*a*a%mo;}while(b>>=1);return ans;}
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

int main() {
	std::ios::sync_with_stdio(false);
	int N;
	ll K;
	cin >> N >> K;
	std::multiset<std::pair<ll, ll> > AtoBs;
	REP(n, N) {
		ll A, B;
		cin >> A >> B;
		AtoBs.emplace(A, B);
	}

	ll current = K;
	while (!AtoBs.empty() && AtoBs.begin()->first <= current) {
		current += AtoBs.begin()->second;
		AtoBs.erase(AtoBs.begin());
	}
	cout << current << endl;
}
