```go
package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	in := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(in, &n)

	w1 := make([]int, 0)
	w2 := make([]int, 0)
	totalW := 0
	for i := 0; i < n; i++ {
		var t, w int
		fmt.Fscan(in, &t, &w)
		totalW += w
		if t == 1 {
			w1 = append(w1, w)
		} else {
			w2 = append(w2, w)
		}
	}

	negInf := -1 << 30
	dp := make([]int, totalW+1)
	for i := range dp {
		dp[i] = negInf
	}
	dp[0] = 0

	for _, w := range w1 {
		ndp := make([]int, totalW+1)
		copy(ndp, dp)
		for sw := 0; sw+w <= totalW; sw++ {
			if dp[sw] == negInf {
				continue
			}
			if dp[sw]+1 > ndp[sw+w] {
				ndp[sw+w] = dp[sw] + 1
			}
		}
		dp = ndp
	}
	for _, w := range w2 {
		ndp := make([]int, totalW+1)
		copy(ndp, dp)
		for sw := 0; sw+w <= totalW; sw++ {
			if dp[sw] == negInf {
				continue
			}
			if dp[sw]+2 > ndp[sw+w] {
				ndp[sw+w] = dp[sw] + 2
			}
		}
		dp = ndp
	}

	ans := 1 << 30
	for sv := 0; sv <= totalW; sv++ {
		tv := dp[sv]
		if tv == negInf {
			continue
		}
		hw := totalW - sv
		if hw <= tv && tv < ans {
			ans = tv
		}
	}

	fmt.Print(ans)
}
```