# include <stdio.h>
# include <string.h>
# include <iostream>
# include <algorithm>using namespace std;typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;const int M = 1e5 + 10, N = 27;
const int mod = 12015858;int n;
int l[N], r[N];char str[N];
inline void gin(int &x) {scanf("%s", str);if(!isdigit(str[0])) x = -(str[0] - 'a' + 1);else {x = 0;for (int i=0; str[i]; ++i) x = (x<<3) + (x<<1) + str[i] - '0';}
}int head[N], nxt[M], to[M], tot = 0;
inline void add(int u, int v) {++tot; nxt[tot] = head[u]; head[u] = tot; to[tot] = v;
}
inline void adde(int u, int v) {
//    cout << u << " --> " << v << endl;
    add(u, v), add(v, u);
}int f[N][M], s[N][M];
// 到了x这个点，x的取值为i
inline void dfs(int x, int fa = 0) {for (int i=1; i<=100000; ++i) f[x][i] = 1;for (int i=head[x]; i; i=nxt[i]) {if(to[i] == fa) continue;dfs(to[i], x);int y = to[i];for (int j=1; j<=100000; ++j) {if(l[y] < 0) {if(j <= r[y]) f[x][j] = 1ll * f[x][j] * (s[y][r[y]] - s[y][j-1]) % mod;else f[x][j] = 0;}if(r[y] < 0) {if(l[y] <= j) f[x][j] = 1ll * f[x][j] * (s[y][j] - s[y][l[y]-1]) % mod;else f[x][j] = 0;}if(f[x][j] < 0) f[x][j] += mod;}}for (int i=1; i<=100000; ++i) {s[x][i] = s[x][i-1] + f[x][i];if(s[x][i] >= mod) s[x][i] -= mod;
//        if(i <= 100) cout << x << ' ' << i << ' ' << f[x][i] << endl;
    }
}int main() {
//    freopen("car.in", "r", stdin);
//    freopen("car.out", "w", stdout);cin >> n;for (int i=1; i<=n; ++i) {gin(l[i]), gin(r[i]);//    cout << l[i] << ' ' << r[i] << endl;if(l[i] < 0) adde(-l[i], i);if(r[i] < 0) adde(-r[i], i);}ll ans = 1, times;for (int i=1; i<=n; ++i) {if(l[i] < 0 || r[i] < 0) continue;dfs(i); ans = ans * (s[i][r[i]] - s[i][l[i]-1]) % mod;}ans = (ans + mod) % mod;cout << ans;return 0;
}