// yukicoder: No.771 しおり
// 2019.8.3 bal4u

#include <stdio.h>
#include <string.h>

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif
int in() {   // 非負整数の入力
	int n = 0, c = gc();
	//	while (isspace(c)) c = gc();
	do n = 10 * n + (c & 0xf); while ((c = gc()) >= '0');
	return n;
}

#define INF 0x77777777
#define MAX 19
int N;
int a[MAX], b[MAX];
int dp[1<<MAX][MAX];

int calc(int N) {
	int s, u, v, x, ans;
	int lim = (1 << N)-1;
	
	memset(dp, INF, sizeof(dp));
	for (u = 0; u < N; u++) dp[1<<u][u] = 0;
	for (s = 0; s <= lim; s++) {
		for (u = 0; u < N; u++) if ((s>>u) & 1) for (v = 0; v < N; v++) {
			if ((s>>v) & 1) continue;
			x = dp[s][u] >= b[u]+a[v]? dp[s][u]: b[u]+a[v];
			int *p = &dp[s | (1<<v)][v];
			if (x < *p) *p = x;
		}
	}
	ans = INF;
	for (u = lim; u >= 0; u--) {
		if (ans > dp[lim][u]) ans = dp[lim][u];
	}
	return ans;
}

int main()
{
	int i, j;

	N = in();
	for (i = 0; i < N; i++) a[i] = in(), b[i] = in()-a[i];
	printf("%d\n", calc(N));
	return 0;
}