Bob came to a cash & carry store, put n items into his trolley, and went to the checkout counter to pay. Each item is described by its price ci and time ti in seconds that a checkout assistant spends on this item. While the checkout assistant is occupied with some item, Bob can steal some other items from his trolley. To steal one item Bob needs exactly 1 second. What is the minimum amount of money that Bob will have to pay to the checkout assistant? Remember, please, that it is Bob, who determines the order of items for the checkout assistant.

Input

The first input line contains number n (1 ≤ n ≤ 2000). In each of the following n lines each item is described by a pair of numbers ti, ci (0 ≤ ti ≤ 2000, 1 ≤ ci ≤ 109). If ti is 0, Bob won't be able to steal anything, while the checkout assistant is occupied with item i.

Output

Output one number — answer to the problem: what is the minimum amount of money that Bob will have to pay.

Examples

Input

4
2 10
0 20
1 5
1 3


Output

8


Input

3
0 1
0 10
0 100


Output

111
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.lang.reflect.Constructor;
import java.util.Arrays;
import java.util.Comparator;
import java.util.StringTokenizer;

public class CodeG 
{
	static class Scanner
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer("");
		
		public String nextLine()
		{
			try
			{
				return br.readLine();
			}
			catch(Exception e)
			{
				throw(new RuntimeException());
			}
		}
		
		public String next()
		{
			while(!st.hasMoreTokens())
			{
				String l = nextLine();
				if(l == null)
					return null;
				st = new StringTokenizer(l);
			}
			return st.nextToken();
		}
		
		public int nextInt()
		{
			return Integer.parseInt(next());
		}
		
		public long nextLong()
		{
			return Long.parseLong(next());
		}
		
		public double nextDouble()
		{
			return Double.parseDouble(next());
		}
		
		public int[] nextIntArray(int n)
		{
			int[] res = new int[n];
			for(int i = 0; i < res.length; i++)
				res[i] = nextInt();
			return res;
		}
		
		public long[] nextLongArray(int n)
		{
			long[] res = new long[n];
			for(int i = 0; i < res.length; i++)
				res[i] = nextLong();
			return res;
		}
		
		public double[] nextDoubleArray(int n)
		{
			double[] res = new double[n];
			for(int i = 0; i < res.length; i++)
				res[i] = nextDouble();
			return res;
		}
		public void sortIntArray(int[] array)
		{
			Integer[] vals = new Integer[array.length];
			for(int i = 0; i < array.length; i++)
				vals[i] = array[i];
			Arrays.sort(vals);
			for(int i = 0; i < array.length; i++)
				array[i] = vals[i];
		}
		
		public void sortLongArray(long[] array)
		{
			Long[] vals = new Long[array.length];
			for(int i = 0; i < array.length; i++)
				vals[i] = array[i];
			Arrays.sort(vals);
			for(int i = 0; i < array.length; i++)
				array[i] = vals[i];
		}
		
		public void sortDoubleArray(double[] array)
		{
			Double[] vals = new Double[array.length];
			for(int i = 0; i < array.length; i++)
				vals[i] = array[i];
			Arrays.sort(vals);
			for(int i = 0; i < array.length; i++)
				array[i] = vals[i];
		}

		public String[] nextStringArray(int n) 
		{	
			String[] vals = new String[n];
			for(int i = 0; i < n; i++)
				vals[i] = next();
			return vals;
		}
		
		public Integer nextInteger()
		{
			String s = next();
			if(s == null)
				return null;
			return Integer.parseInt(s);
		}
		
		public int[][] nextIntMatrix(int n, int m)
		{
			int[][] ans = new int[n][];
			for(int i = 0; i < n; i++)
				ans[i] = nextIntArray(m);
			return ans;
		}
		
		public char[][] nextGrid(int r, int c) 
		{
			char[][] grid = new char[r][];
			for(int i = 0; i < r; i++)
				grid[i] = next().toCharArray();
			return grid;
		}
		
		public static <T> T fill(T arreglo, int val)
		{
			if(arreglo instanceof Object[])
			{
				Object[] a = (Object[]) arreglo;
				for(Object x : a)
					fill(x, val);
			}
			else if(arreglo instanceof int[])
				Arrays.fill((int[]) arreglo, val);
			else if(arreglo instanceof double[])
				Arrays.fill((double[]) arreglo, val);
			else if(arreglo instanceof long[])
				Arrays.fill((long[]) arreglo, val);
			return arreglo;
		}
		
		<T> T[] nextObjectArray(Class <T> clazz, int size)
		{
			@SuppressWarnings("unchecked")
			T[] result = (T[]) java.lang.reflect.Array.newInstance(clazz, size);
			for(int c = 0; c < 3; c++)
			{
				Constructor <T> constructor;
				try 
				{
					if(c == 0)
						constructor = clazz.getDeclaredConstructor(Scanner.class, Integer.TYPE);
					else if(c == 1)
						constructor = clazz.getDeclaredConstructor(Scanner.class);
					else
						constructor = clazz.getDeclaredConstructor();
				} 
				catch(Exception e)
				{
					continue;
				}
				try
				{
					for(int i = 0; i < result.length; i++)
					{
						if(c == 0)
							result[i] = constructor.newInstance(this, i);
						else if(c == 1)
							result[i] = constructor.newInstance(this);
						else
							result[i] = constructor.newInstance();	
					}
				}
				catch(Exception e)
				{
					throw new RuntimeException(e);
				}
				return result;
			}
			throw new RuntimeException("Constructor not found");
		}
		
		public void printLine(int... vals)
		{
			if(vals.length == 0)
				System.out.println();
			else
			{
				System.out.print(vals[0]);
				for(int i = 1; i < vals.length; i++)
					System.out.print(" ".concat(String.valueOf(vals[i])));
				System.out.println();
			}
		}
		
		public void printLine(long... vals)
		{
			if(vals.length == 0)
				System.out.println();
			else
			{
				System.out.print(vals[0]);
				for(int i = 1; i < vals.length; i++)
					System.out.print(" ".concat(String.valueOf(vals[i])));
				System.out.println();
			}
		}
		
		public void printLine(double... vals)
		{
			if(vals.length == 0)
				System.out.println();
			else
			{
				System.out.print(vals[0]);
				for(int i = 1; i < vals.length; i++)
					System.out.print(" ".concat(String.valueOf(vals[i])));
				System.out.println();
			}
		}
		
		public void printLine(int prec, double... vals)
		{
			if(vals.length == 0)
				System.out.println();
			else
			{
				System.out.printf("%." + prec + "f", vals[0]);
				for(int i = 1; i < vals.length; i++)
					System.out.printf(" %." + prec + "f", vals[i]);
				System.out.println();
			}
		}
	}
	
	static int[][] people;
	static long[][] dp;
	static int n;
	
	static long dp(int i, int remaining)
	{
		if(dp[i][remaining + n] != -1) return dp[i][remaining + n];
		if(i == people.length) return dp[i][remaining + n] = remaining >= 0 ? 0 : Long.MIN_VALUE;
		long best = Long.MIN_VALUE;
		best = Math.max(best, people[i][1] + dp(i + 1, remaining - 1));
		best = Math.max(best, dp(i + 1, Math.min(people.length, remaining + people[i][0])));
		return dp[i][remaining + n] = best;
	}
	
	public static void main(String[] args)
	{
		Scanner sc = new Scanner();
		n = sc.nextInt();
		people = sc.nextIntMatrix(n, 2);
		Arrays.sort(people, new Comparator<int[]> () {

			@Override
			public int compare(int[] o1, int[] o2) 
			{
				return o2[0] - o1[0];
			}
		});
		long total = 0;
		for(int[] p : people)
			total += p[1];
		dp = Scanner.fill(new long[n + 10][2 * n + 10], -1);
		System.out.println(total - dp(0, 0));
	}
}