import sys
read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines

n = int(readline())
p = sorted([list(map(int, readline().split())) for _ in range(n)], key=lambda x: sum(x))
dp = [-1 for _ in range(10010)]
dp[0] = 0
ans = 0
for i in range(n):
    for j in range(10010):
        if 0 <= j - p[i][0] < p[i][1] and dp[j-p[i][0]] >= 0:
            dp[j] = max(dp[j], dp[j-p[i][0]] + 1)
            ans = max(ans, j)
print(ans)