#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
static const double pi = 3.141592653589793;
const ll INF = 1LL << 60;
const ll mod = 1000000007;
const ll imod = 998244353;
using mint = modint998244353;
vector<int> dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
ll P(ll x, ll n) {
  ll ret = 1;
    while (n > 0) {
      if (n & 1) ret *= x;
      x *= x;
      n >>= 1;
  }
  return ret;
}

void seek(bool f){
  cout << (f ? "Yes" : "No") << endl;
}

int main(){
	ll N;
	cin >> N;
	vector<ll> A(N), B(N);
	rep(i, N){
		cin >> A[i] >> B[i];
	}
	map<ll, ll> ma;
	rep(i, N){
		ll res = 2;
		while(A[i] % res == 0){
			res *= 2;
		}
		if(res == 2){
			ma[0] += B[i];
		}
		else if(res == 4){
			ma[1] += B[i];
		}
		else if(res == 8){
			ma[2] += B[i];
		}
		else if(res >= 16){
			ma[3] += B[i];
		}
	}
	ll ans = 0;
	ans += ma[3];
	if(ma[1] <= ma[2]){
		ans += ma[1];
		ma[2] -= ma[1];
		ans += ma[2] / 2;
	}
	else{
		ans += ma[2];
		ma[1] -= ma[2];
		ans += ma[1] / 3;
	}
	cout << ans << endl;
	
}