#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int main()
{
    double n,m,a;
    
        cin>>n>>m;
       // scanf("%lf%lf",n,m);
        a=100-((double)(100/n)*m);
        printf("%.2lf",a);
        
    
}
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define ll long long
#define ld long double
#define all(a) (a).begin(),(a).end()
#define mk make_pair
#define pp pair<ll,ll>
ll MOD=1000000007;
ll mod=998244353;
int inf=1000001000;
ll INF=1e18+5;

int main() {
   int n;
   ll k;
   cin >> n >> k;
   vector<pp> a(n);
   rep(i,n) cin >> a[i].first >> a[i].second;
   sort(all(a));
   ll ans=0;
   rep(i,n){
       if (k>=a[i].first){
           k+=a[i].second;
       }
       else break;
   }
   cout << k << endl;
}
