floyd

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#define not !
#define and &&
#define or ||

#define r() fast_read()
#define rep(inc, frm, to) for (size_t inc = frm; inc < (to); ++inc)

#define MAX_N 110
#define oo 0x3f3f3f3f

typedef long long int ll;

ll fast_read(void) {
  ll n = 0, sign = 1;
  char c = getchar();
  while (c < 48 or c > 57) {
    if (c == '-') sign = ~0;
    c = getchar();
  }
  while (c >= 48 and c <= 57) {
    n = (n << 1) + (n << 3) + (c ^ 48);
    c = getchar();
  }
  return sign * n;
}

int n, dp[MAX_N][MAX_N], a[MAX_N], ans = oo;

void init_dp(void) {
  rep(i, 1, n + 1) rep(j, 1, n + 1) dp[i][j] = i == j ? 0 : oo;
}

void print_dp(void) {
  rep(i, 1, n + 1) rep(j, 1, n + 1) printf("%10d%c", *(*(dp + i) + j), j == n ? 10 : 32);
  putchar(10);
}

void floyd(void) {
  rep(k, 1, n + 1) rep(i, 1, n + 1) rep(j, 1, n + 1) dp[i][j] = fmin(dp[i][j], dp[i][k] + dp[k][j]);
}

int main(int argc, char const *argv[]) {
  // freopen("test.in", "r", stdin);
  n = r();
  init_dp();
  int x, y;
  rep(i, 1, n + 1) {
    *(a + i) = r();
    x = r(), y = r();
    if (x) dp[i][x] = dp[x][i] = 1;
    if (y) dp[i][y] = dp[y][i] = 1;
  }
  floyd();
  rep(i, 1, n + 1) {
    int tot = 0;
    rep(j, 1, n + 1) tot += dp[j][i] * a[j];
    ans = fmin(ans, tot);
  }

  printf("%d", ans);
  // fclose(stdin);
  return 0;
}