#include<cstdio>
#include<cstring>
#include<algorithm>
#include<functional>
#include<utility>
#define rep(i,a) for(int i=0;i<(a);++i)
#define clr(a,v) memset((a),(v),sizeof(a))

typedef std::pair<int, int> P;

const int MAX_N = 10000;

int N;
P ps[MAX_N];
int dp[MAX_N][MAX_N+1];

int rec( int i, int c )
{
	if( i == N )
		return c;

	int &ret = dp[i][c];
	if( ~ret )
		return ret;

	if( c >= ps[i].first )
		return ret = rec( i+1, c );
	else
		return ret = std::max( rec( i+1, c ), rec( i+1, std::min( MAX_N, c+ps[i].second ) ) );
}

int main()
{
	scanf( "%d", &N );
	rep( i, N )
	{
		int V, T;
		scanf( "%d%d", &V, &T );
		ps[i] = P( T, V );
	}

	std::sort( ps, ps+N, []( const P &lhs, const P &rhs ){ return lhs.first+lhs.second < rhs.first+rhs.second; }  );
	clr( dp, -1 );

	printf( "%d\n", rec( 0, 0 ) );

	return 0;
}