#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<map>
#include<cmath>
#include<queue>
#include<stack>
#include<deque>
#include<list>
#include<bitset>
#include<sstream>

using namespace std;
using ll = long long;
const ll MOD = 1e9+7;
const ll INF = 1e18;
#define REP(i, n) for(int i = 0; i < n; i++)
#define endl "\n"
using Graph = vector<vector<int>>;

int main(){
    double a,b;
    cin>>a>>b;
    printf("%.10lf\n",a*b/100);
}
#pragma region head
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;
using pi = pair<int, int>;
using pll = pair<ll, ll>;
template <class T>
using vv = vector<vector<T>>;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repi(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rrepi(i, a, b) for (int i = (int)(b)-1; i >= (int)(a); i--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define bit(n) (1LL << (n))
template <class T>
inline bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline bool chmin(T &a, const T &b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}
const int INF = 1002003004;
const ll LINF = 1002003004005006007ll;
struct preprocess {
    preprocess() {
        cin.tie(nullptr);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(20);
    }
} ____;
#pragma endregion head

#pragma region library
#pragma endregion library

int main() {
    int n;
    cin >> n;
    vi a(n), b(n);
    rep(i, n) cin >> a[i] >> b[i];
    ll now = accumulate(all(a), 0ll);
    vll diff(n);
    rep(i, n) {
        diff[i] = a[i] * 2ll + b[i];
    }
    sort(rall(diff));
    int ans = 0;
    int idx = 0;
    while (idx < n && now >= 0) {
        now -= diff[idx++];
        ans++;
    }
    cout << ans << '\n';
}
